标签：dfs

速算24点

A 2 3 6
3 3 8 8

Yes
No

题意。。。。

就是模板

代码：

#include <iostream>
#include <cstdio>
#include <cstring>
const int M = 50;

int num[M];
bool vis[M];

int dfs(int n, int top){
    if(n == 1){
        if(24 == num[top-1]) return 1;
        return 0;
    }
    for(int i = 0; i < top; ++ i){
        if(!vis[i]){
            vis[i] = 1;
            for(int j = i+1; j < top; ++ j){
                if(!vis[j]){
                    vis[j] = 1;

                    num[top] = num[i]+num[j];
                    if(dfs(n-1, top+1)) return 1;

                    num[top] = num[i]-num[j];
                    if(dfs(n-1, top+1)) return 1;

                    num[top] = num[j]-num[i];
                    if(dfs(n-1, top+1)) return 1;

                    num[top] = num[i]*num[j];
                    if(dfs(n-1, top+1)) return 1;

                    if(num[j]&&num[i]%num[j] == 0){
                        num[top] = num[i]/num[j];
                        if(dfs(n-1, top+1)) return 1;
                    }

                    if(num[i]&&num[j]%num[i] == 0){
                        num[top] = num[j]/num[i];
                        if(dfs(n-1, top+1)) return 1;
                    }

                    vis[j] = 0;
                }
            }
            vis[i] = 0;
        }
    }
    return 0;
}

int main(){
    int i = 0;
    char s[2];
    while(scanf("%s", s) == 1){
        if(s[0] >= '2'&&s[0] <= '9'){
            num[i++] = s[0]-'0';
        }
        else if(s[0] == 'A') num[i++] = 1;
        else if(s[0] == 'J') num[i++] = 11;
        else if(s[0] == 'Q') num[i++] = 12;
        else if(s[0] == '1') num[i++] = 10;
        else num[i++] = 13;
        int t = 3;
        while(t --){
            scanf("%s", s);
             if(s[0] >= '2'&&s[0] <= '9'){
                num[i++] = s[0]-'0';
            }
            else if(s[0] == 'A') num[i++] = 1;
            else if(s[0] == 'J') num[i++] = 11;
            else if(s[0] == 'Q') num[i++] = 12;
            else if(s[0] == '1') num[i++] = 10;
            else num[i++] = 13;
        }
        memset(vis, 0, sizeof(vis));
        if(dfs(4, 4)) puts("Yes");
        else puts("No");
        i = 0;
    }
    return 0;
}

Hdoj 1427 速算24点 【DFS】

标签：dfs

原文地址：http://blog.csdn.net/shengweisong/article/details/45256807