Submission #1275866

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Source Code Expand

#include "bits/stdc++.h"

#define REP(i,n) for(ll i=0;i<n;++i)
#define RREP(i,n) for(ll i=n-1;i>=0;--i)
#define FOR(i,m,n) for(ll i=m;i<n;++i)
#define RFOR(i,m,n) for(ll i=n-1;i>=m;--i)
#define ALL(v) (v).begin(),(v).end()
#define PB(a) push_back(a)
#define UNIQUE(v) v.erase(unique(ALL(v)),v.end());
#define DUMP(v) REP(i, (v).size()) { cout << v[i]; if (i != v.size() - 1)cout << " "; else cout << endl; }
#define INF 1000000001ll
#define MOD 1000000007ll
#define EPS 1e-9

const int dx[8] = { 1,1,0,-1,-1,-1,0,1 };
const int dy[8] = { 0,1,1,1,0,-1,-1,-1 };


using namespace std;
typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int, int> pii;
typedef pair<ll, ll> pll;
ll max(ll a, int b) { return max(a, ll(b)); }
ll max(int a, ll b) { return max(ll(a), b); }
ll min(ll a, int b) { return min(a, ll(b)); }
ll min(int a, ll b) { return min(ll(a), b); }
///(´・ω・`)(´・ω・`)(´・ω・`)(´・ω・`)(´・ω・`)(´・ω・`)///
int main() {
	cin.tie(0);
	ios::sync_with_stdio(false);
	int t;
	cin >> t;
	REP(x, t) {
		int n;
		cin >> n;
		vvi v(n, vi(n));
		REP(i, n)REP(j, n)cin >> v[i][j];
		int flag = 1;
		REP(i, n) {
			REP(j, n) {
				REP(k, n) {
					if (v[i][k] != -1 && v[k][j] != -1 && v[i][j] > v[i][k] + v[k][j])flag = 0;
				}
			}
		}
		REP(i, n)if (v[i][i] != 0)flag = 0;
		if (flag)cout << "YES" << endl;
		else cout << "NO" << endl;
	}
	return 0;
}

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