Submission #1982954

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Source Code Expand

#include <bits/stdc++.h>
#define REP(i,a,b) for(int i=(a);i<(b);i++)
#define RREP(i,a,b) for(int i=(a);i>=(b);i--)
#define pq priority_queue
#define P pair<int,int>
#define P2 pair<int,P>
#define P3 pair<int,P2>
typedef long long ll; typedef long double ld;
using namespace std;
const int INF=1e9, MOD=1e9+7, around[]={0,1,1,-1,-1,0,-1,1,0,0};
const ll LINF=1e18;
const ld PI=abs(acos(-1));
int Q,n,a[30][30],b[30][30];

int main(){
	cin >> Q;
	
	REP(q,0,Q){
		cin >> n;
		bool f=true;
		REP(i,0,n) REP(j,0,n) cin >> a[i][j],b[i][j]=a[i][j];
		REP(i,0,n) if(a[i][i]!=0) f=false;
		REP(i,0,n) REP(j,0,n) if(a[i][j]==-1) a[i][j]=b[i][j]=INF;
		
		REP(k,0,n) REP(i,0,n) REP(j,0,n) a[i][j]=min(a[i][j], a[i][k]+a[k][j]);
		REP(i,0,n) REP(j,0,n) if(a[i][j]!=b[i][j]) f=false;
		
		
		cout << (f?"YES":"NO") << endl;
	}

	return 0;
}

Submission Info

Judge Result