hdu 1427 24点暴力dfs

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#include <iostream>#include <cstdio>#include <algorithm>using namespace std;int num;int a[4],x;const int inf=1<<10;  // 括号改变的运算符的优先级所以  //a@b@c@d            符号的全排列有 3!种可能  由于数字可以调换  ((a@b)@c) @d  等价于 a @ ((b@c)@d )     要想使(i,j,k,l) 的优先级为 a @ ((b@c)@d ) 等价于  j,k,l,i 在 ((a@b)@c) @d 所以这种情况保留一个就好 int calc(int op,int b,int c)  {switch(op){case 1: return b+c;case 2: return b-c;case 3: return b*c;case 4: if(c!=0&&b%c==0) return b/c;else return inf;}}bool fun1()  // ((a@b)@c)@d{int i,j,k;int k1,k2,ans;for(i=1;i<=4;i++){k1=calc(i,a[0],a[1]);if(k1==inf) continue;for(j=1;j<=4;j++){k2=calc(j,k1,a[2]);if(k2==inf) continue;for(k=1;k<=4;k++){ans=calc(k,k2,a[3]);if(ans==inf) continue;if(ans==24)return 1;}}}return 0;}bool fun2() // (a@b)@(c@d){int i,j,k;int k1,k2,ans;for(i=1;i<=4;i++){k1=calc(i,a[0],a[1]);if(k1==inf) continue;for(j=1;j<=4;j++){k2=calc(j,a[2],a[3]);if(k2==inf) continue;for(k=1;k<=4;k++){ans=calc(k,k1,k2);if(ans==inf) continue;if(ans==24)return 1;}}}return 0;}bool fun3() // (a@(b@c))@d{int i,j,k;double k1,k2,ans;for(i=1;i<=4;i++){k1=calc(i,a[1],a[2]);if(k1==inf) continue;for(j=1;j<=4;j++){k2=calc(j,a[0],k1);if(k2==inf) continue;for(k=1;k<=4;k++){ans=calc(k,k2,a[3]);if(ans==inf) continue;if(ans==24)return 1;}}}return 0;}int main(){char b[5];int t,i;while(1){int f=0;for(i=0;i<4;i++){if(scanf("%s",b)==EOF) return 0;if(b[0]=='A'){a[i]=1;continue;}if(b[0]=='J'){a[i]=11;continue;}if(b[0]=='Q'){a[i]=12;continue;}if(b[0]=='K'){a[i]=13;continue;}if(b[0]=='1'&&b[1]=='0')//{a[i]=10;continue;}a[i]=b[0]-'0';}sort(a,a+4);do{ //生成数字的全排列 if(fun1()){f=1;break;}if(fun2()){f=1;break;}if(fun3()){f=1;break;}}while(next_permutation(a,a+4));if(f){cout<<"Yes"<<endl;}else{cout<<"No"<<endl;}}return 0;}
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