The dragon 选一只老鼠，然后会跑掉一只
the princess选一只老鼠，不会跑出另外的老鼠
求the princess赢的概率
1 #include<iostream> 2 #include<string> 3 #include<cstdio> 4 #include<vector> 5 #include<queue> 6 #include<stack> 7 #include<algorithm> 8 #include<cstring> 9 #include<stdlib.h> 10 #include<cmath> 11 using namespace std; 12 #define pb push_back 13 double dp[1010][1010]; 14 int main(){ 15 int w,b; 16 while(cin>>w>>b){ 17 memset(dp,0,sizeof(dp)); 18 dp[1][0]=1; 19 for(int i=1;i<=w;i++) 20 for(int j=0;j<=b;j++){ 21 double p1,p2; 22 int a=i,b=j; 23 dp[i][j]=1.0*i/(i+j); 24 if(b>=1){ 25 p1=1.0*b/(a+b); 26 b--; //the princess选了一只 27 if(b>=1){ 28 p2=1.0*b/(a+b);//The dragon 选一只 29 b--; 30 if(b>=1) 31 dp[i][j]+=p1*p2*b/(a+b)*dp[i][j-3]; 32 dp[i][j]+=p1*p2*a/(a+b)*dp[i-1][j-2]; 33 } 34 } 35 } 36 printf("%.10lf ",dp[w][b]); 37 } 38 }