Problem:
All Pairs Shortest Path

Input

An edge-weighted graph G (V, E).

|V| |E|
s0 t0 d0
s1 t1 d1
:
s|E|-1 t|E|-1 d|E|-1

|V| is the number of vertices and |E| is the number of edges in G. The graph vertices are named with the numbers 0, 1,..., |V|-1 respectively.

si and ti represent source and target vertices of i-th edge (directed) and di represents the cost of the i-th edge.

Output

If the graph contains a negative cycle (a cycle whose sum of edge costs is a negative value), print

NEGATIVE CYCLE

in a line.

Otherwise, print

D0,0 D0,1 ... D0,|V|-1
D1,0 D1,1 ... D1,|V|-1
:
D|V|-1,0 D1,1 ... D|V|-1,|V|-1

The output consists of |V| lines. For each ith line, print the cost of the shortest path from vertex i to each vertex j (j = 0, 1, ... |V|-1) respectively. If there is no path from vertex i to vertex j, print "INF". Print a space between the costs.

Constraints

1 ≤ |V| ≤ 100

0 ≤ |E| ≤ 9900

-2 × 107 ≤ di ≤ 2 × 107

There are no parallel edges

There are no self-loops

Sample Input 1

4 6
0 1 1
0 2 5
1 2 2
1 3 4
2 3 1
3 2 7

Sample Output 1

0 1 3 4
INF 0 2 3
INF INF 0 1
INF INF 7 0

Sample Input 2

4 6
0 1 1
0 2 -5
1 2 2
1 3 4
2 3 1
3 2 7

Sample Output 2

0 1 -5 -4
INF 0 2 3
INF INF 0 1
INF INF 7 0

Sample Input 3

4 6
0 1 1
0 2 5
1 2 2
1 3 4
2 3 1
3 2 -7

Sample Output 3

NEGATIVE CYCLE

Solution in C# (judge verdict: Wrong Answer)

using System;
using System.Text;
using System.Collections.Generic;
using System.Linq;
class Solve{
    public Solve(){}
    StringBuilder sb;
    public static int Main(){
        new Solve().Run();
        return 0;
    }
    void Run(){
        sb = new StringBuilder();
        Calc();
        Console.Write(sb.ToString());
    }
    void Calc(){
        string[] str = Console.ReadLine().Split(' ');
        int N = int.Parse(str[0]);
        int E = int.Parse(str[1]);
        long[,] cost = new long[N,N];
        long INF = 1000000000000000;
        for(int i=0;i<N;i++){
            for(int j=0;j<N;j++){
                if(i != j){
                    cost[i,j] = INF;
                }
            }
        }
        for(int i=0;i<E;i++){
            str = Console.ReadLine().Split(' ');
            int f = int.Parse(str[0]);
            int t = int.Parse(str[1]);
            cost[f,t] = Math.Min(int.Parse(str[2]),cost[f,t]);
        }
        for(int i=0;i<N;i++){
            for(int j=0;j<N;j++){
                for(int k=0;k<N;k++){
                    if(cost[i,k] != INF && cost[k,j] != INF){
                        cost[i,j] = Math.Min(cost[i,j],cost[i,k]+cost[k,j]);
                    }
                }
            }
        }
        bool NegativeCycle = false;
        for(int i=0;i<N;i++){
            if(cost[i,i] < 0){
                NegativeCycle = true;
            }
        }
        if(NegativeCycle){
            sb.Append("NEGATIVE CYCLE\n");
        }
        else{
            for(int i=0;i<N;i++){
                for(int j=0;j<N-1;j++){
                    sb.Append(cost[i,j] == INF ? "INF " : (cost[i,j]+" "));
                }
                sb.Append(cost[i,N-1] == INF ? "INF" : (cost[i,N-1]+""));
                sb.Append("\n");
            }
        }
    }
}