题解 | #24点游戏算法#

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
double num[4];
int vis[4];
int dfs(int step,double sum)
{
    if(step == 3 && sum == 24)
    {
        return 1;
    }else {
        step++;
        for(int i=0;i<4;i++)
        {
            if(vis[i]==0){
                vis[i]=1;
                if(dfs(step,sum+num[i])||
                dfs(step,sum-num[i])||
                dfs(step,sum*num[i])||
                dfs(step,sum/num[i]))
                {
                    return 1;
                }  
                vis[i]=0;
            }
        }
    }
    return 0;
}
int main() {
    
    scanf("%lf %lf %lf %lf",&num[0],&num[1],&num[2],&num[3]);
    
    memset(vis,0,sizeof(vis));
    if(dfs(-1,0))
    {
        printf("true\n");
    }else {
        printf("false\n");
    }

}