Shortest Path

    1#include <bits/stdc++.h>
    2 
    3using namespace std;
    4 
    5vector<int> bellman_ford(int v, vector<vector<int>>& edge, int src){
    6    vector<int> dist(v + 1, 1e8);
    7    dist[src] = 0;
    8    for(int i = 0; i < v; i++){
    9        for(auto e : edge){
    10            int u = e[0], v_ = e[1], w = e[2];
    11            if(dist[u] != 1e8 && dist[u] + w < dist[v_]){
    12                if(i == v - 1) return {-1};
    13                dist[v_] = dist[u] + w;
    14            }
    15        }
    16    }
    17    return dist;
    18}
    19int main(){
    20    ios::sync_with_stdio(0);
    21    cin.tie(0);
    22    vector<vector<int>> edge;
    23    int n, m;
    24    cin >> n >> m;
    25    for(int i = 0; i < m; i++){
    26        int u, v, w;
    27        cin >> u >> v >> w;
    28        edge.push_back(vector<int>{u, v, w});
    29    }
    30    int src = 1;
    31    vector<int> ans = bellman_ford(n, edge, src);
    32    cout << ans[n] << '\n';
    33    return 0;
    34}