51nod 1090 3个数和为0

#include <bits/stdc++.h>using namespace std;set<long long> st;long long a[1010];int main(){long long n,i,j,tmp,flag;while(cin>>n){st.clear();for(i=1;i<=n;i++){scanf("%lld",&a[i]);st.insert(a[i]);}flag=1;sort(a+1,a+1+n);for(i=1;i<=n;i++){for(j=i+1;j<=n;j++){tmp=-a[i]-a[j];if(tmp<=a[j])continue;if(st.find(tmp)!=st.end()){printf("%lld %lld %lld\n",a[i],a[j],tmp);flag=0;}}}if(flag)printf("No Solution\n");} }