Cod sursa(job #2976761)

Utilizator gabriel10tm@gmail.comGabriel Marian [email protected] Data 9 februarie 2023 22:52:55
Problema Algoritmul Bellman-Ford Scor 100
Compilator cpp-64 Status done
Runda Arhiva educationala Marime 1.32 kb
#include <bits/stdc++.h>
using namespace std;
const int nmx = 5e4 + 50'004;
vector<array<int,2>> ad[nmx];
#if 1
#define cin fin
#define cout fout
ifstream fin("bellmanford.in");
ofstream fout("bellmanford.out");
#endif
const int64_t INF = 1e17;
int n,m;
bool spfa(vector<int64_t>& d) {
    d.assign(n, INF);
    vector<int> cnt(nmx, 0);
    vector<bool> inqueue(nmx, 0);
    queue<int> q;

    d[1] = 0;
    q.push(1);
    inqueue[1] = 1;
    while (!q.empty()) {
        int v = q.front();
        q.pop();
        inqueue[v] = 0;

        for (auto edge : ad[v]) {
            int to = edge[0];
            int64_t len = edge[1];

            if (d[v] + len < d[to]) {
                d[to] = d[v] + len;
                if (!inqueue[to]) {
                    q.push(to);
                    inqueue[to] = 1;
                    cnt[to]++;
                    if (cnt[to] > n)
                        return 0;  // negative cycle
                }
            }
        }
    }
    return 1;
}

int main(){
    cin >> n >> m;
    while(m--){
        int u,v,c;
        cin >> u >> v >> c;
        ad[u].push_back({v,c});
    }
    vector<int64_t> d(nmx,INF);
    if(spfa(d)){
        for(int i=2;i<=n;i++)
            cout << d[i] << " ";
    }else{
        cout << "Ciclu negativ!";
    }
}