[백준 11404] 플로이드 (Floyd-Warshall) (C/C++)

#include <stdio.h>
#include <iostream>
#include <vector>
#include <map>
using namespace std;
 
int cityNum, busNum;
int start;
int d[110][110];
map<pair<int, int>, int> visited;
 
void floyd()
{
    for(int k = 1; k <= cityNum; k++)
    {
        for(int i = 1; i <= cityNum; i++)
        {
            for(int j = 1; j <= cityNum; j++)
            {
                if(d[i][k] + d[k][j] < d[i][j])
                {
                    d[i][j] = d[i][k] + d[k][j];
                }
            }
        }
    }
}
 
int main(void)
{
//    freopen("B11404_input.txt", "r", stdin);
    
    cin >> cityNum >> busNum;
    
    for(int i = 1; i <= cityNum; i++)
    {
        for(int j = 1; j <= cityNum; j++)
        {
            d[i][j] = 199999999;
        }
    }
    
    for(int i = 1; i <= busNum; i++)
    {
        int from, to, weight;
        cin >> from >> to >> weight;
        
        if(visited[{from, to}] == 0)
        {
            d[from][to] = weight;    
            visited[{from, to}] = 1;    
        }
        else
        {
            if(weight < d[from][to])
            {
                d[from][to] = weight;
            }
        }
    }
    
    floyd();
    
    for(int i = 1; i <= cityNum; i++)
    {
        for(int j = 1; j <= cityNum; j++)
        {
            // i와 j가 같은 경우는 항상 최소비용 0 
            if(i == j)
            {
                cout << "0 ";
            }
            // i에서 j로 갈 수 없는 경우 
            else if(d[i][j] == 199999999)
            {
                cout << "0 ";
            }
            else
            {
                cout << d[i][j] << " ";            
            }
        }
        cout << endl;
    }
    
    return 0;
}