Submission #684612

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Source Code Expand

#include<bits/stdc++.h>
using namespace std;

#define int long long
typedef pair<int,int>pint;
typedef vector<int>vint;
typedef vector<pint>vpint;
#define pb push_back
#define mp make_pair
#define fi first
#define se second
#define all(v) (v).begin(),(v).end()
#define rep(i,n) for(int i=0;i<(n);i++)
#define reps(i,f,n) for(int i=(f);i<(n);i++)
#define each(it,v) for(__typeof((v).begin()) it=(v).begin();it!=(v).end();it++)
template<class T,class U>inline void chmin(T &t,U f){if(t>f)t=f;}
template<class T,class U>inline void chmax(T &t,U f){if(t<f)t=f;}

const int INF=1001001001;
int N;
int A[30][30];
int B[30][30];
void solve(){
    cin>>N;
    rep(i,N)rep(j,N)cin>>A[i][j];

    rep(i,N){
        if(A[i][i]!=0){
            cout<<"NO"<<endl;
            return;
        }
    }

    rep(i,N)rep(j,N){
        if(A[i][j]==-1)B[i][j]=INF;
        else B[i][j]=A[i][j];
    }
    rep(k,N)rep(i,N)rep(j,N)chmin(B[i][j],B[i][k]+B[k][j]);
    rep(i,N)rep(j,N){
        if((A[i][j]==-1&&B[i][j]!=INF)||(A[i][j]>=0&&A[i][j]!=B[i][j])){
            cout<<"NO"<<endl;
            return;
        }
    }
    cout<<"YES"<<endl;
}

signed main(){
    int T;cin>>T;
    while(T--)solve();
    return 0;
}

Submission Info

Judge Result