题目链接：https://hihocoder.com/problemset/problem/1304
1 #include<cstdio> 2 #include<cstring> 3 #include<cmath> 4 int num[4],nums[4]; 5 char op[6]={'+','-','*','/','#','$'}; 6 char ops[3]; 7 8 int vis[4]; 9 10 double cal(double x,double y,char oop) 11 { 12 switch(oop) 13 { 14 case '+': return x+y; 15 case '-': return x-y; 16 case '*': return x*y; 17 case '/': return x/y; 18 case '#': return y-x; 19 case '$': return y/x; 20 } 21 } 22 23 double pd1 () 24 { 25 double x=cal((double)nums[0],(double)nums[1],ops[0]); 26 double y=cal(x,(double)nums[2],ops[1]); 27 return cal(y,(double)nums[3],ops[2]); 28 29 } 30 31 double pd2 () 32 { 33 double x=cal((double)nums[0],(double)nums[1],ops[0]); 34 double y=cal((double)nums[2],(double)nums[3],ops[2]); 35 return cal(x,y,ops[1]); 36 37 38 } 39 40 int makeops(int dep) 41 { 42 if(dep==3) 43 { 44 if(fabs(pd1()-24.0)<1.0e-2) return 1; //¾ø¶ÔÖµ 45 if(fabs(pd2()-24.0)<1.0e-2) return 1; 46 return 0; 47 } 48 49 for(int i=0;i<6;i++) 50 { 51 ops[dep]=op[i]; 52 if(makeops(dep+1)) return 1; 53 } 54 return 0; 55 56 } 57 58 59 int makenums(int dep) 60 { 61 if(dep==4) { 62 return makeops(0); 63 } 64 for(int i=0;i<4;i++) 65 { 66 if(!vis[i]) 67 { 68 nums[dep]=num[i]; 69 vis[i]=1; 70 if(makenums(dep+1)) return 1; 71 vis[i]=0; 72 } 73 74 } 75 return 0; 76 } 77 78 int main() 79 { 80 int t; 81 scanf("%d",&t); 82 while(t--){ 83 memset(vis,0,sizeof(vis)); 84 for(int i=0;i<4;i++) 85 scanf("%d",&num[i]); 86 if(makenums(0)) puts("Yes"); 87 else puts("No"); 88 } 89 return 0; 90 }