POJ 3440 Coin Toss（求概率）

 1 //3440
 2 #include <stdio.h>
 3 #include <string.h>
 4 #include <iostream>
 5 #include <math.h>
 6 #define PI acos(-1.0)
 7 
 8 using namespace std ;
 9 
10 int main()
11 {
12     int k;
13     double a1,a2,a3,a4,sum;
14     double c,m,n,t;
15     scanf("%d",&k) ;
16     for(int i = 1 ; i <= k ; i++){
17        scanf("%lf %lf %lf %lf",&m,&n,&t,&c) ;
18         sum = m*n*t*t;
19         a1 = (t-c)*(t-c)*n*m+(c*(t-c)+c*c/4.0)*4+c*(t-c)*(n+m-4) ;
20         a2 = (m-1)*n*t*c+(n-1)*m*t*c-2*(m-1)*(n-1)*c*c;
21         a3 = (m-1)*(n-1)*c*c*(1-PI/4);
22         a4 = (m-1)*(n-1)*c*c*PI/4;
23         printf("Case %d:\n",i);
24         printf("Probability of covering 1 tile  = %.4f%%\n",100*a1/sum);
25         printf("Probability of covering 2 tiles = %.4f%%\n",100*a2/sum);
26         printf("Probability of covering 3 tiles = %.4f%%\n",100*a3/sum);
27         printf("Probability of covering 4 tiles = %.4f%%\n",100*a4/sum);
28         printf("\n");
29     }
30     return 0 ;
31 }