zoj 1204 Additive equations

zoj 1204 Additive equations

#include <cstdio>#include <iostream>#include <algorithm>#include <cstring>using namespace std;int n;int a[35];bool vis[35], flag;void DFS(int start, int len, int sum){    if(len == 0)    {        for(int i = start; i<n && sum>=a[i]; ++i)        { if(sum == a[i]) {     flag = true;     for(int j = 0; j <= i; ++j)     {         if(vis[j])         {  if(sum == a[j])        printf("%d=%dn", a[j], a[i]);  else      printf("%d+", a[j]);  sum -= a[j];         }     } }        }    }    else    {        for(int i = start; i<n; ++i)        { if(sum + a[i] <= a[n-1]) {     sum += a[i];     vis[i] = true;     --len;     DFS(i+1, len, sum);     sum -= a[i];     vis[i] = false;     ++len; }        }    }}int main(){    int T;    scanf("%d", &T);    while(T--)    {        scanf("%d", &n);        for(int i = 0; i < n; ++i) scanf("%d", &a[i]);        sort(a, a+n);        memset(vis, false, sizeof(vis));        flag = false;        for(int i = 2; i < n; ++i) DFS(0, i, 0);        if(!flag) printf("Can't find any equations.nn");        else printf("n");    }    return 0;}