。终 Board。。。。恭喜杜教取得 #7 的冠军。。虽然没有 AK。。还是被她得到了《xxx 写真集》。。。。。04 最终三个程序通过。。2 个树套树一个分块（Java 的）。。。。。。。。注：04 的 pretest 和 systest 一样但居然还有 RP 爆炸 fst 的。（卡过了 pre 没卡过 systest。。。）。。。。。
http://bestcoder.hdu.edu.cn/contests/contest_show.php?cid=531
1001 Little Pony and Permutation
题意：
求一个循环的循环分解。
分析：
直接 while 循环搞搞就好了。
1002 Little Pony and Alohomora Part I
http://acm.hdu.edu.cn/showproblem.php?pid=4986
题意：
求随机排列的期望循环个数。
分析：
【引理 1】对于一个随机排列的某个元素，处在一个长度为 $$k$$ 的循环中的概率为 $$1/n$$（与循环的长度无关）。
证明：
方法一：
考察某个元素处在长度为 $k$ 的循环中的方案数，有：
$$!\binom{n-1}{k-1}(k-1)!(n-k)! = (n-1)! $$
比上总的方案数得到概率:
$$!\frac{(n-1)!}{n!} = \frac{1}{n}$$
方法二：
。。。
我们可以用第一题的方法，将每个排列写成 Cycle Notation，并将每个循环中最小的元素放在末尾。
那么每一个排列的 Cycle Notation 和另一个排列可以建立起一一对应。而 1 处在的循环中的长度等于它在排列中的位置，因此所有长度的概率都是 $$\frac{1}{n}$$。
——————————
考虑 dp 。。设 e[n] 表示长度为 n 的排列的循环个数的期望。。我们枚举其中一个循环的长度。根据期望可加。。有。。。
$$!e[n] = \frac{\sum_{i=1}^n e[n-i]}{n} $$
也就是 e[n] = H[n] （调和级数）
对于调和级数，可以较小项暴力，较大项时用 log() 近似。
（当然似乎找规律也能过。。。。。）
1003 Little Pony and Dice
http://acm.hdu.edu.cn/showproblem.php?pid=4987
题意：
有一个 $$m$$ 面的均匀骰子（[1, $$m$$]），然后从 0 出发，根据扔的数字，决定向前走的步数，走到 $$\geq n$$ 时就停止。
求刚好在 $$n$$ 停止的概率。要求误差 $$10^{-5}$$ 以内。（$$1\leq m, n\leq 10^9$$）
分析：
当 $$m$$ 很大时，概率会接近 0，由于误差 $$10^{-5}$$，当 $$n\geq 600000$$ 时，直接返回 0。。
（。。。$$n=m$$ 时的答案约是 $$e^{-1/n}$$。。.因此实际这个值大约是 550000 左右。。。）
- 当 $$m\geq n$$ 时：
设 f[i] 表示距离 n 还有 i 步时所求的概率，有：
f[i] = sigma j < i (dp[j])/m f[i-1] = sigma j < i-1 (dp[j])/m f[i] - f[i-1] = dp[i-1]/m f[i] = f[i-1]*(1+1/m) 初值 f[1] = 1/m
解得：
$$!f[n] = \frac{(1+1/m)^{n-1}}{m}$$。
当 $$n$$ 很大后，因为这个值会很快收敛的 $$ 2/(m+1) $$。。
考虑 DP，并用部分和优化到 $$O(n)$$。
#include <cstdlib>
#include <cctype>
#include <cstring>
#include <cstdio>
#include <cmath>
#include <algorithm>
#include <vector>
#include <string>
#include <iostream>
#include <sstream>
#include <map>
#include <set>
#include <queue>
#include <stack>
#include <fstream>
#include <numeric>
#include <iomanip>
#include <bitset>
#include <list>
#include <stdexcept>
#include <functional>
#include <utility>
#include <ctime>
#include <cassert>
#include <complex>
using namespace std;
#define rep(i,a,n) for (int i=a;i<n;i++)
#define per(i,a,n) for (int i=n-1;i>=a;i--)
#define pb push_back
#define mp make_pair
#define all(x) (x).begin(),(x).end()
#define fi first
#define se second
#define SZ(x) ((int)(x).size())
#define ACCU accumulate
#define TWO(x) (1<<(x))
#define TWOL(x) (1ll<<(x))
#define clr(a) memset(a,0,sizeof(a))
#define POSIN(x,y) (0<=(x)&&(x)<n&&0<=(y)&&(y)<m)
#define PRINTC(x) cout<<"Case #"<<++__<<": "<<x<<endl
#define POP(x) (__builtin_popcount(x))
#define POPL(x) (__builtin_popcountll(x))
typedef vector<int> VI;
typedef vector<string> VS;
typedef vector<double> VD;
typedef long long ll;
typedef long double LD;
typedef pair<int,int> PII;
typedef pair<ll,ll> PLL;
typedef vector<ll> VL;
typedef vector<PII> VPII;
typedef complex<double> CD;
const int inf=0x20202020;
const ll mod=1000000007;
const double eps=1e-9;
const double pi=3.1415926535897932384626;
const int DX[]={1,0,-1,0},DY[]={0,1,0,-1};
ll powmod(ll a,ll b) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll powmod(ll a,ll b,ll mod) {ll res=1;a%=mod;for(;b;b>>=1){if(b&1)res=res*a%mod;a=a*a%mod;}return res;}
ll gcd(ll a,ll b) { return b?gcd(b,a%b):a;}
// head
const int N=1000000;
double dp[N+100],s[N+100];
int n,m;
int main() {
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
freopen("out.txt", "w", stdout);
#endif
while (scanf("%d%d",&m,&n)!=EOF) {
if (m>=600000) puts("0.00000");
else {
if (n<=m) printf("%.5f\n",pow(1+1./m,n-1)/m);
else {
dp[0]=1; s[0]=1;
for (int i=1;i<=n;i++) {
if (i<=m) dp[i]=s[i-1]/m;
else dp[i]=(s[i-1]-s[i-m-1])/m;
s[i]=s[i-1]+dp[i];
if (i>=m&&abs(dp[i]-2./(m+1))<=1e-9) { n=i;break;}
}
printf("%.5f\n",dp[n]);
}
}
}
}
1004 Little Pony and Boast Busters
http://acm.hdu.edu.cn/showproblem.php?pid=4988
题意：
给定上下两个排列 A[], B[]，要求询问相同项之间两两连线的交叉数，并支持交换操作。。。
分析：
。。。静态问题就是求排列 P[] 的逆序对。。
其中 P[i] = pA[B[i]]。 （这里 pA[] 是 A[] 中某个元素的位置。。类似的 pB[] 是 B[] 中某个元素的位置。。。）
考察交换操作。。无论是交换下排还是上排，都可以看成交换 P[] 中的两项。。。
对于交换下排。。。
swap(B[a], B[b]); pB[B[a]]=a,pB[B[b]]=b, swap(P[a], P[b]);
对于交换上排。。有。
swap(A[a],A[b]); pA[A[a]]=a,pA[A[b]]=b, swap(P[pB[A[a]]], P[pB[A[b]]]);
于是转化成动态逆序对问题，支持修改排列中的任意一项。
动态逆序对问题等价于区间 kth 大值（区间 Rank）问题。。可以用经典的树套树方法。。。
。。复杂度 $$O(nlog^2n)$$。
/** Micro Mezz Macro Flation -- Overheated Economy ., Last Update: Aug. 17th 2014 **/ //{
/** Header .. **/ //{
#pragma comment(linker, "/STACK:36777216")
//#pragma GCC optimize ("O2")
#define LOCAL
//#include "testlib.h"
#include <functional>
#include <algorithm>
#include <iostream>
#include <fstream>
#include <sstream>
#include <iomanip>
#include <numeric>
#include <cstring>
#include <climits>
#include <cassert>
#include <complex>
#include <cstdio>
#include <string>
#include <vector>
#include <bitset>
#include <queue>
#include <stack>
#include <cmath>
#include <ctime>
#include <list>
#include <set>
#include <map>
//#include <tr1/unordered_set>
//#include <tr1/unordered_map>
//#include <array>
using namespace std;
#define REP(i, n) for (int i=0;i<n;++i)
#define FOR(i, a, b) for (int i=a;i<b;++i)
#define DWN(i, b, a) for (int i=b-1;i>=a;--i)
#define REP_1(i, n) for (int i=1;i<=n;++i)
#define FOR_1(i, a, b) for (int i=a;i<=b;++i)
#define DWN_1(i, b, a) for (int i=b;i>=a;--i)
#define REP_C(i, n) for (int n____=n,i=0;i<n____;++i)
#define FOR_C(i, a, b) for (int b____=b,i=a;i<b____;++i)
#define DWN_C(i, b, a) for (int a____=a,i=b-1;i>=a____;--i)
#define REP_N(i, n) for (i=0;i<n;++i)
#define FOR_N(i, a, b) for (i=a;i<b;++i)
#define DWN_N(i, b, a) for (i=b-1;i>=a;--i)
#define REP_1_C(i, n) for (int n____=n,i=1;i<=n____;++i)
#define FOR_1_C(i, a, b) for (int b____=b,i=a;i<=b____;++i)
#define DWN_1_C(i, b, a) for (int a____=a,i=b;i>=a____;--i)
#define REP_1_N(i, n) for (i=1;i<=n;++i)
#define FOR_1_N(i, a, b) for (i=a;i<=b;++i)
#define DWN_1_N(i, b, a) for (i=b;i>=a;--i)
#define REP_C_N(i, n) for (int n____=(i=0,n);i<n____;++i)
#define FOR_C_N(i, a, b) for (int b____=(i=0,b);i<b____;++i)
#define DWN_C_N(i, b, a) for (int a____=(i=b-1,a);i>=a____;--i)
#define REP_1_C_N(i, n) for (int n____=(i=1,n);i<=n____;++i)
#define FOR_1_C_N(i, a, b) for (int b____=(i=a,b);i<=b____;++i)
#define DWN_1_C_N(i, b, a) for (int a____=(i=b,a);i>=a____;--i)
#define ECH(it, A) for (__typeof(A.begin()) it=A.begin(); it != A.end(); ++it)
#define REP_S(i, str) for (char*i=str;*i;++i)
#define REP_L(i, hd, suc) for (int i=hd;i;i=suc[i])
#define REP_G(i, u) REP_L(i,hd[u],suc)
#define REP_SS(x, s) for (int x=s;x;x=(x-1)&s)
#define DO(n) for ( int ____n = n; ____n-->0; )
#define REP_2(i, j, n, m) REP(i, n) REP(j, m)
#define REP_2_1(i, j, n, m) REP_1(i, n) REP_1(j, m)
#define REP_3(i, j, k, n, m, l) REP(i, n) REP(j, m) REP(k, l)
#define REP_3_1(i, j, k, n, m, l) REP_1(i, n) REP_1(j, m) REP_1(k, l)
#define REP_4(i, j, k, ii, n, m, l, nn) REP(i, n) REP(j, m) REP(k, l) REP(ii, nn)
#define REP_4_1(i, j, k, ii, n, m, l, nn) REP_1(i, n) REP_1(j, m) REP_1(k, l) REP_1(ii, nn)
#define ALL(A) A.begin(), A.end()
#define LLA(A) A.rbegin(), A.rend()
#define CPY(A, B) memcpy(A, B, sizeof(A))
#define INS(A, P, B) A.insert(A.begin() + P, B)
#define ERS(A, P) A.erase(A.begin() + P)
#define LBD(A, x) (lower_bound(ALL(A), x) - A.begin())
#define UBD(A, x) (upper_bound(ALL(A), x) - A.begin())
#define CTN(T, x) (T.find(x) != T.end())
#define SZ(A) int((A).size())
#define PB push_back
#define MP(A, B) make_pair(A, B)
#define PTT pair<T, T>
#define Ts *this
#define rTs return Ts
#define fi first
#define se second
#define re real()
#define im imag()
#define Rush for(int ____T=RD(); ____T--;)
#define Display(A, n, m) { \
REP(i, n){ \
REP(j, m-1) cout << A[i][j] << " "; \
cout << A[i][m-1] << endl; \
} \
}
#define Display_1(A, n, m) { \
REP_1(i, n){ \
REP_1(j, m-1) cout << A[i][j] << " "; \
cout << A[i][m] << endl; \
} \
}
typedef long long LL;
//typedef long double DB;
typedef double DB;
typedef unsigned uint;
typedef unsigned long long uLL;
typedef vector<int> VI;
typedef vector<char> VC;
typedef vector<string> VS;
typedef vector<LL> VL;
typedef vector<DB> VF;
typedef set<int> SI;
typedef set<string> SS;
typedef map<int, int> MII;
typedef map<string, int> MSI;
typedef pair<int, int> PII;
typedef pair<LL, LL> PLL;
typedef vector<PII> VII;
typedef vector<VI> VVI;
typedef vector<VII> VVII;
template<class T> inline T& RD(T &);
template<class T> inline void OT(const T &);
//inline int RD(){int x; return RD(x);}
inline LL RD(){LL x; return RD(x);}
inline DB& RF(DB &);
inline DB RF(){DB x; return RF(x);}
inline char* RS(char *s);
inline char& RC(char &c);
inline char RC();
inline char& RC(char &c){scanf(" %c", &c); return c;}
inline char RC(){char c; return RC(c);}
//inline char& RC(char &c){c = getchar(); return c;}
//inline char RC(){return getchar();}
template<class T> inline T& RDD(T &);
inline LL RDD(){LL x; return RDD(x);}
template<class T0, class T1> inline T0& RD(T0 &x0, T1 &x1){RD(x0), RD(x1); return x0;}
template<class T0, class T1, class T2> inline T0& RD(T0 &x0, T1 &x1, T2 &x2){RD(x0), RD(x1), RD(x2); return x0;}
template<class T0, class T1, class T2, class T3> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3){RD(x0), RD(x1), RD(x2), RD(x3); return x0;}
template<class T0, class T1, class T2, class T3, class T4> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4); return x0;}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5); return x0;}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline T0& RD(T0 &x0, T1 &x1, T2 &x2, T3 &x3, T4 &x4, T5 &x5, T6 &x6){RD(x0), RD(x1), RD(x2), RD(x3), RD(x4), RD(x5), RD(x6); return x0;}
template<class T0, class T1> inline void OT(const T0 &x0, const T1 &x1){OT(x0), OT(x1);}
template<class T0, class T1, class T2> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2){OT(x0), OT(x1), OT(x2);}
template<class T0, class T1, class T2, class T3> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3){OT(x0), OT(x1), OT(x2), OT(x3);}
template<class T0, class T1, class T2, class T3, class T4> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4, const T5 &x5){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void OT(const T0 &x0, const T1 &x1, const T2 &x2, const T3 &x3, const T4 &x4, const T5 &x5, const T6 &x6){OT(x0), OT(x1), OT(x2), OT(x3), OT(x4), OT(x5), OT(x6);}
inline char& RC(char &a, char &b){RC(a), RC(b); return a;}
inline char& RC(char &a, char &b, char &c){RC(a), RC(b), RC(c); return a;}
inline char& RC(char &a, char &b, char &c, char &d){RC(a), RC(b), RC(c), RC(d); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e){RC(a), RC(b), RC(c), RC(d), RC(e); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e, char &f){RC(a), RC(b), RC(c), RC(d), RC(e), RC(f); return a;}
inline char& RC(char &a, char &b, char &c, char &d, char &e, char &f, char &g){RC(a), RC(b), RC(c), RC(d), RC(e), RC(f), RC(g); return a;}
inline DB& RF(DB &a, DB &b){RF(a), RF(b); return a;}
inline DB& RF(DB &a, DB &b, DB &c){RF(a), RF(b), RF(c); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d){RF(a), RF(b), RF(c), RF(d); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e){RF(a), RF(b), RF(c), RF(d), RF(e); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e, DB &f){RF(a), RF(b), RF(c), RF(d), RF(e), RF(f); return a;}
inline DB& RF(DB &a, DB &b, DB &c, DB &d, DB &e, DB &f, DB &g){RF(a), RF(b), RF(c), RF(d), RF(e), RF(f), RF(g); return a;}
inline void RS(char *s1, char *s2){RS(s1), RS(s2);}
inline void RS(char *s1, char *s2, char *s3){RS(s1), RS(s2), RS(s3);}
template<class T0,class T1>inline void RDD(T0&a, T1&b){RDD(a),RDD(b);}
template<class T0,class T1,class T2>inline void RDD(T0&a, T1&b, T2&c){RDD(a),RDD(b),RDD(c);}
template<class T> inline void RST(T &A){memset(A, 0, sizeof(A));}
template<class T> inline void FLC(T &A, int x){memset(A, x, sizeof(A));}
template<class T> inline void CLR(T &A){A.clear();}
template<class T0, class T1> inline void RST(T0 &A0, T1 &A1){RST(A0), RST(A1);}
template<class T0, class T1, class T2> inline void RST(T0 &A0, T1 &A1, T2 &A2){RST(A0), RST(A1), RST(A2);}
template<class T0, class T1, class T2, class T3> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3){RST(A0), RST(A1), RST(A2), RST(A3);}
template<class T0, class T1, class T2, class T3, class T4> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4), RST(A5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void RST(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6){RST(A0), RST(A1), RST(A2), RST(A3), RST(A4), RST(A5), RST(A6);}
template<class T0, class T1> inline void FLC(T0 &A0, T1 &A1, int x){FLC(A0, x), FLC(A1, x);}
template<class T0, class T1, class T2> inline void FLC(T0 &A0, T1 &A1, T2 &A2, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x);}
template<class T0, class T1, class T2, class T3> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x);}
template<class T0, class T1, class T2, class T3, class T4> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x), FLC(A5, x);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void FLC(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6, int x){FLC(A0, x), FLC(A1, x), FLC(A2, x), FLC(A3, x), FLC(A4, x), FLC(A5, x), FLC(A6, x);}
template<class T> inline void CLR(priority_queue<T, vector<T>, less<T> > &Q){while (!Q.empty()) Q.pop();}
template<class T> inline void CLR(priority_queue<T, vector<T>, greater<T> > &Q){while (!Q.empty()) Q.pop();}
template<class T> inline void CLR(stack<T> &S){while (!S.empty()) S.pop();}
template<class T> inline void CLR(queue<T> &Q){while (!Q.empty()) Q.pop();}
template<class T0, class T1> inline void CLR(T0 &A0, T1 &A1){CLR(A0), CLR(A1);}
template<class T0, class T1, class T2> inline void CLR(T0 &A0, T1 &A1, T2 &A2){CLR(A0), CLR(A1), CLR(A2);}
template<class T0, class T1, class T2, class T3> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3){CLR(A0), CLR(A1), CLR(A2), CLR(A3);}
template<class T0, class T1, class T2, class T3, class T4> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4);}
template<class T0, class T1, class T2, class T3, class T4, class T5> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4), CLR(A5);}
template<class T0, class T1, class T2, class T3, class T4, class T5, class T6> inline void CLR(T0 &A0, T1 &A1, T2 &A2, T3 &A3, T4 &A4, T5 &A5, T6 &A6){CLR(A0), CLR(A1), CLR(A2), CLR(A3), CLR(A4), CLR(A5), CLR(A6);}
template<class T> inline void CLR(T &A, int n){REP(i, n) CLR(A[i]);}
template<class T> inline bool EPT(T &a){return a.empty();}
template<class T> inline T& SRT(T &A){sort(ALL(A)); return A;}
template<class T, class C> inline T& SRT(T &A, C B){sort(ALL(A), B); return A;}
template<class T> inline T& RVS(T &A){reverse(ALL(A)); return A;}
template<class T> inline T& UNQQ(T &A){A.resize(unique(ALL(A))-A.begin());return A;}
template<class T> inline T& UNQ(T &A){SRT(A);return UNQQ(A);}
//}
/** Constant List .. **/ //{
const int MOD = int(1e9) + 7;
const int INF = 0x3f3f3f3f;
const LL INFF = 0x3f3f3f3f3f3f3f3fLL;
const DB EPS = 1e-9;
const DB OO = 1e20;
const DB PI = acos(-1.0); //M_PI;
const int dx[] = {-1, 0, 1, 0};
const int dy[] = {0, 1, 0, -1};
//}
/** Add On .. **/ //{
// <<= '0. Nichi Joo ., //{
template<class T> inline T& checkMin(T &a,const T b){if (b<a) a=b;return a;}
template<class T> inline T& checkMax(T &a,const T b){if (a<b) a=b;return a;}
template<class T> inline T& checkMin(T &a, T &b, const T x){checkMin(a, x), checkMin(b, x);return a;}
template<class T> inline T& checkMax(T &a, T &b, const T x){checkMax(a, x), checkMax(b, x);return a;}
template <class T, class C> inline T& checkMin(T& a, const T b, C c){if (c(b,a)) a = b;return a;}
template <class T, class C> inline T& checkMax(T& a, const T b, C c){if (c(a,b)) a = b;return a;}
template<class T> inline T min(T a, T b, T c){return min(min(a, b), c);}
template<class T> inline T max(T a, T b, T c){return max(max(a, b), c);}
template<class T> inline T min(T a, T b, T c, T d){return min(min(a, b), min(c, d));}
template<class T> inline T max(T a, T b, T c, T d){return max(max(a, b), max(c, d));}
template<class T> inline T min(T a, T b, T c, T d, T e){return min(min(min(a,b),min(c,d)),e);}
template<class T> inline T max(T a, T b, T c, T d, T e){return max(max(max(a,b),max(c,d)),e);}
template<class T> inline T sqr(T a){return a*a;}
template<class T> inline T cub(T a){return a*a*a;}
template<class T> inline T ceil(T x, T y){return (x - 1) / y + 1;}
template<class T> T abs(T x){return x>0?x:-x;}
inline int sgn(DB x){return x < -EPS ? -1 : x > EPS;}
inline int sgn(DB x, DB y){return sgn(x - y);}
inline DB cos(DB a, DB b, DB c){return (sqr(a)+sqr(b)-sqr(c))/(2*a*b);}
inline DB cot(DB x){return 1./tan(x);};
inline DB sec(DB x){return 1./cos(x);};
inline DB csc(DB x){return 1./sin(x);};
//}
// <<= '1. Bitwise Operation ., //{
namespace BO{
inline bool _1(int x, int i){return bool(x&1<<i);}
inline bool _1(LL x, int i){return bool(x&1LL<<i);}
inline LL _1(int i){return 1LL<<i;}
inline LL _U(int i){return _1(i) - 1;};
inline int reverse_bits(int x){
x = ((x >> 1) & 0x55555555) | ((x << 1) & 0xaaaaaaaa);
x = ((x >> 2) & 0x33333333) | ((x << 2) & 0xcccccccc);
x = ((x >> 4) & 0x0f0f0f0f) | ((x << 4) & 0xf0f0f0f0);
x = ((x >> 8) & 0x00ff00ff) | ((x << 8) & 0xff00ff00);
x = ((x >>16) & 0x0000ffff) | ((x <<16) & 0xffff0000);
return x;
}
inline LL reverse_bits(LL x){
x = ((x >> 1) & 0x5555555555555555LL) | ((x << 1) & 0xaaaaaaaaaaaaaaaaLL);
x = ((x >> 2) & 0x3333333333333333LL) | ((x << 2) & 0xccccccccccccccccLL);
x = ((x >> 4) & 0x0f0f0f0f0f0f0f0fLL) | ((x << 4) & 0xf0f0f0f0f0f0f0f0LL);
x = ((x >> 8) & 0x00ff00ff00ff00ffLL) | ((x << 8) & 0xff00ff00ff00ff00LL);
x = ((x >>16) & 0x0000ffff0000ffffLL) | ((x <<16) & 0xffff0000ffff0000LL);
x = ((x >>32) & 0x00000000ffffffffLL) | ((x <<32) & 0xffffffff00000000LL);
return x;
}
template<class T> inline bool odd(T x){return x&1;}
template<class T> inline bool even(T x){return !odd(x);}
template<class T> inline T low_bit(T x) {return x & -x;}
template<class T> inline T high_bit(T x) {T p = low_bit(x);while (p != x) x -= p, p = low_bit(x);return p;}
template<class T> inline T cover_bit(T x){T p = 1; while (p < x) p <<= 1;return p;}
template<class T> inline int cover_idx(T x){int p = 0; while (_1(p) < x ) ++p; return p;}
inline int clz(int x){return __builtin_clz(x);}
inline int clz(LL x){return __builtin_clzll(x);}
inline int ctz(int x){return __builtin_ctz(x);}
inline int ctz(LL x){return __builtin_ctzll(x);}
inline int lg2(int x){return !x ? -1 : 31 - clz(x);}
inline int lg2(LL x){return !x ? -1 : 63 - clz(x);}
inline int low_idx(int x){return !x ? -1 : ctz(x);}
inline int low_idx(LL x){return !x ? -1 : ctz(x);}
inline int high_idx(int x){return lg2(x);}
inline int high_idx(LL x){return lg2(x);}
inline int parity(int x){return __builtin_parity(x);}
inline int parity(LL x){return __builtin_parityll(x);}
inline int count_bits(int x){return __builtin_popcount(x);}
inline int count_bits(LL x){return __builtin_popcountll(x);}
} using namespace BO;//}
// <<= '2. Number Theory .,//{
namespace NT{
#define gcd __gcd
inline LL lcm(LL a, LL b){return a*b/gcd(a,b);}
inline void INC(int &a, int b){a += b; if (a >= MOD) a -= MOD;}
inline int sum(int a, int b){a += b; if (a >= MOD) a -= MOD; return a;}
/* ģ�������պó� int ʱ��
inline int sum(uint a, int b){a += b; a %= MOD;if (a < 0) a += MOD; return a;}
inline void INC(int &a, int b){a = sum(a, b);}
*/
inline void DEC(int &a, int b){a -= b; if (a < 0) a += MOD;}
inline int dff(int a, int b){a -= b; if (a < 0) a += MOD; return a;}
inline void MUL(int &a, int b){a = (LL)a * b % MOD;}
inline int pdt(int a, int b){return (LL)a * b % MOD;}
inline int gcd(int m, int n, int &x, int &y){
x = 1, y = 0; int xx = 0, yy = 1, q;
while (1){
q = m / n, m %= n;
if (!m){x = xx, y = yy; return n;}
DEC(x, pdt(q, xx)), DEC(y, pdt(q, yy));
q = n / m, n %= m;
if (!n) return m;
DEC(xx, pdt(q, x)), DEC(yy, pdt(q, y));
}
}
inline int sum(int a, int b, int c){return sum(a, sum(b, c));}
inline int sum(int a, int b, int c, int d){return sum(sum(a, b), sum(c, d));}
inline int pdt(int a, int b, int c){return pdt(a, pdt(b, c));}
inline int pdt(int a, int b, int c, int d){return pdt(pdt(a, b), pdt(c, d));}
inline int pow(int a, LL b){
int c(1); while (b){
if (b&1) MUL(c, a);
MUL(a, a), b >>= 1;
}
return c;
}
template<class T> inline T pow(T a, LL b){
T c(1); while (b){
if (b&1) c *= a;
a *= a, b >>= 1;
}
return c;
}
template<class T> inline T pow(T a, int b){
return pow(a, (LL)b);
}
inline int _I(int b){
int a = MOD, x1 = 0, x2 = 1, q; while (1){
q = a / b, a %= b;
if (!a) return x2;
DEC(x1, pdt(q, x2));
q = b / a, b %= a;
if (!b) return x1;
DEC(x2, pdt(q, x1));
}
}
inline void DIV(int &a, int b){MUL(a, _I(b));}
inline int qtt(int a, int b){return pdt(a, _I(b));}
} using namespace NT;//}
//}
/** I/O Accelerator Interface .. **/ //{
#define g (c=getchar())
#define d isdigit(g)
#define p x=x*10+c-'0'
#define n x=x*10+'0'-c
#define pp l/=10,p
#define nn l/=10,n
template<class T> inline T& RD(T &x){
char c;while(!d);x=c-'0';while(d)p;
return x;
}
template<class T> inline T& RDD(T &x){
char c;while(g,c!='-'&&!isdigit(c));
if (c=='-'){x='0'-g;while(d)n;}
else{x=c-'0';while(d)p;}
return x;
}
inline DB& RF(DB &x){
//scanf("%lf", &x);
char c;while(g,c!='-'&&c!='.'&&!isdigit(c));
if(c=='-')if(g=='.'){x=0;DB l=1;while(d)nn;x*=l;}
else{x='0'-c;while(d)n;if(c=='.'){DB l=1;while(d)nn;x*=l;}}
else if(c=='.'){x=0;DB l=1;while(d)pp;x*=l;}
else{x=c-'0';while(d)p;if(c=='.'){DB l=1;while(d)pp;x*=l;}}
return x;
}
#undef nn
#undef pp
#undef n
#undef p
#undef d
#undef g
inline char* RS(char *s){
//gets(s);
scanf("%s", s);
return s;
}
LL last_ans; int Case; template<class T> inline void OT(const T &x){
//printf("Case #%d: ", ++Case);
//printf("%lld\n", x);
//printf("%.9f\n", x);
//printf("%d\n", x);
cout << x << endl;
//last_ans = x;
}
//}
//}/* .................................................................................................................................. */
const int N = int(1e5) + 9, LV = 25;
namespace SBT{
const int NN = N*LV;
int c[2][NN], sz[NN], ky[NN], tot;
#define lx l[x]
#define rx r[x]
#define l c[d]
#define r c[!d]
#define kx ky[x]
#define sx sz[x]
#define d 0
int new_node(int v = 0){
int x=++tot;lx=rx=0;
sx=1;kx=v;
return x;
}
void upd(int x){
sx=sz[lx]+1+sz[rx];
}
#undef d
void rot(int &x,int d){
int y=rx;rx=l[y];l[y]=x;
upd(x),upd(y),x=y;
}
void fix(int &x,int d){
if (sz[l[lx]] > sz[rx]) rot(x,!d);
else{
if (sz[r[lx]] > sz[rx]) rot(lx,d),rot(x,!d);
else return;
}
d=0,fix(lx,0),fix(rx,1);
fix(x,0),fix(x,1);
}
#define d 0
void Ins(int &x,int v){
if(!x) x = new_node(v);
else{
++sz[x]; Ins(c[v>kx][x],v);
fix(x,v>=kx);
}
}
int d_key; void Del(int &x,int v){
--sx;if(kx==v||(v<kx&&!lx)||(v>kx&&!rx)){
if(!lx||!rx) d_key = kx, x = lx | rx;
else Del(lx,v+1), kx = d_key;
}
else Del(c[v>kx][x],v);
}
int Rank(int x,int v){
int z=0;while(x){
if(kx<v){
z+=sz[lx]+1;
x=rx;
}
else{
x=lx;
}
}
return z;
}
bool Find(int x,int v){
if (!x) return 0;if (kx==v) return 1;
return Find(c[v>kx][x],v);
}
void Init(){
tot = 0;
}
#undef d
#undef l
#undef r
#undef lx
#undef rx
#undef sx
#undef kx
};
LL res;
int n, m;
namespace BIT{
int C[N];
void Ins(int x, int v){
for (;x<=n;x+=low_bit(x)) SBT::Ins(C[x],v);
}
void Del(int x, int v){
for (;x<=n;x+=low_bit(x)) SBT::Del(C[x],v);
}
int Rank(int x, int v){
int res = 0; for (;x;x^=low_bit(x)) res += SBT::Rank(C[x],v);
return res;
}
int Count(int x){
int res = 0; for (;x;x^=low_bit(x)) res += SBT::sz[C[x]];
return res;
}
void Init(){
fill(C+1, C+n+1, 0);
}
};
int A[N], pA[N], B[N], pB[N];
int P[N];
void Init(){
SBT::Init(); BIT::Init(); res = 0; int x;
REP_1(i, n) pA[++RD(A[i])] = i;
REP_1(i, n){
pB[++RD(B[i])] = i; int x = pA[B[i]];
res += i-1-BIT::Rank(n,x+1); //#
BIT::Ins(i, x), P[i] = x;
}
}
#define v P[x]
#define delta ((x-1)-BIT::Rank(x,v+1)+BIT::Rank(n,v)-BIT::Rank(x,v))
void Change(int x, int vv){
BIT::Del(x, v);
res -= delta; v = vv;
res += delta; BIT::Ins(x, v);
}
#undef v
int main(){
#ifndef ONLINE_JUDGE
freopen("in.txt", "r", stdin);
//freopen("out.txt", "w", stdout);
#endif
//#define a A[x]
//#define delta ((x-1)-BIT::Rank(x,a+1)+BIT::Rank(n,a)-BIT::Rank(x,a))
//汇编调栈
int __size__ = 256 << 20; // 256MB
char *__p__ = (char*)malloc(__size__) + __size__;
__asm__("movl %0, %%esp\n" :: "r"(__p__));
while (~scanf("%d", &n)){
Init();
char cmd[9]; Rush{
RS(cmd); if (cmd[0] == 'Q') OT(res);
else{
int p, a, b; RD(p, a, b); ++a, ++b;
if (p == 1){
swap(B[a], B[b]);
pB[B[a]]=a,pB[B[b]]=b,
Change(a, pA[B[a]]);
Change(b, pA[B[b]]);
}
else{
swap(A[a],A[b]);
pA[A[a]]=a,pA[A[b]]=b,
Change(pB[A[a]], a);
Change(pB[A[b]], b);
}
/*REP_1(i, n){
assert(P[i] == pA[B[i]]);
}*/
}
}
}
////int x, aa; RD(x, aa); BIT::Del(x, a);
}
