ZOJ 3329 One Person Game(概率dp 经典)

题目链接：https://vjudge.net/problem/ZOJ-3329

#include<cstdio>#include<cstring>#include<string>#include<cctype>#include<iostream>#include<set>#include<map>#include<cmath>#include<sstream>#include<vector>#include<stack>#include<queue>#include<algorithm>#define fin freopen("a.txt","r",stdin)#define fout freopen("a.txt","w",stdout)typedef long long LL;using namespace std;typedef pair<int, int> P;const int INF = 1e8 + 10;const int maxn = 1000 + 10;double A[maxn], B[maxn], p[maxn], p0;int n, k1, k2, k3, a, b, c;int main(){//fin;int T;scanf("%d", &T);while(T--){cin >> n >> k1 >> k2 >> k3 >> a >> b >> c;        p0 = 1.0/(k1*k2*k3);        memset(p, 0, sizeof p);        memset(A, 0, sizeof A);        memset(B, 0, sizeof B);        for(int i = 1; i <= k1; i++)          for(int j = 1; j <= k2; j++)          for(int k = 1; k <= k3; k++)          if(i != a || j != b || k != c)             p[i+j+k] += p0;        for(int i = n; i >= 0; i--)        {        A[i] = p0; B[i] = 1.0;        for(int k = 3; k + i <= n; k++)        {        A[i] += p[k]*A[i+k];        B[i] += p[k]*B[i+k];        }        }        printf("%.12f\n", B[0]/(1.0-A[0]));}return 0;}