Submission #760433

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Source Code Expand

#include<iostream>
#include<vector>
#include<string>
#include<algorithm>	
#include<map>
#include<set>
#include<utility>
#include<cmath>
#include<cstring>
#include<queue>
#include<cstdio>
#include<sstream>
#define loop(i,a,b) for(int i=a;i<b;i++) 
#define rep(i,a) loop(i,0,a)
#define pb push_back
#define mp make_pair
#define all(in) in.begin(),in.end()
const double PI=acos(-1);
const double EPS=1e-8;
const int inf=1e9;
using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pii;
int main(){
	int q;
	cin>>q;
	while(q--){
		int n;
		cin>>n;
		vvi cost(n,vi(n));
		rep(i,n)rep(j,n)cin>>cost[i][j];
		bool h=true;
		rep(i,n)if(cost[i][i])h=false;
		if(!h){
			cout<<"NO"<<endl;
			continue;
		}
		rep(i,n)rep(j,n)if(cost[i][j]==-1)cost[i][j]=inf;
		vvi tmp=cost;
		rep(k,n)rep(i,n)rep(j,n)
			cost[i][j]=min(cost[i][j],cost[i][k]+cost[k][j]);
//		rep(i,n){rep(j,n)cout<<" "<<cost[i][j];cout<<endl;}
		h=true;
		rep(i,n)rep(j,n)if(cost[i][j]!=tmp[i][j])h=false;
		if(h)cout<<"YES"<<endl;
		else cout<<"NO"<<endl;
	}
}

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