[数据结构与算法]计蒜客（dfs 等边三角形）

代码

#include<bits/stdc++.h>
using namespace std;
int p[25];
int vis[25] = {0};
int n, sum;
bool f = false;
void dfs(int x, int s, int st){
    if(f){
        return;
    }
    if(x == 3){
        f = true;
        return;
    }
    if(s == sum / 3){
        dfs(x + 1, 0, 0);
        return;
    }
    for(int i = st; i < n; i++){
        if(!vis[i]){
            vis[i] = 1;
            dfs(x, s + p[i], i + 1);
            vis[i] = 0;
        }
    }
}

int main()
{
    scanf("%d", &n);
    for(int i = 0; i < n; i++){
        scanf("%d", &p[i]);
        sum += p[i];
    }
    if(sum % 3 != 0){
        printf("no\n");
    }else{
        dfs(0, 0, 0);
        if(f){
            printf("yes\n");
        }else{
            printf("no\n");
        }
    }
    return 0;
}