差分约束

#include<bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef long double ld;
const ll inf = 0x3f3f3f3f;
const ll N = 5e5 + 9;
struct edge {
    ll v, w;
};
vector<edge>G[N];
ll d[N], instk[N], cnt[N];
ll n, m;
void bel_ford(ll s) {
    memset(d, 0x3f, sizeof d);
    memset(instk, 0, sizeof instk);
    memset(cnt, 0, sizeof cnt);
    queue<int>q;
    d[s] = 0;
    instk[s] = 1;
    q.push(s);
    while (!q.empty()) {
        auto u = q.front();
        q.pop();
        instk[u] = 0;// /???????????????????????!!!!!!!!!!!!!!!!!!!!
        for (auto e:G[u]) {
            ll v = e.v;
            if (d[v] > d[u] + e.w) {
                d[v] = d[u] + e.w;
                if (!instk[v]) {
                    instk[v] = 1;
                    cnt[v] ++;
                    q.push(v);
                    if (cnt[v] == n + 1) {//关键，因为有0所以才n + 1
                        cout << "NO
";
                        exit(0);
                    }
                }
            }
        }
    }
}
void solve() {
    cin >> n >> m;
    for (ll i = 1; i <= m; i ++) {
        ll u, v, w;
        cin >> u >> v >> w;
        G[v].push_back({u, w});//关键，必须要反向，因为是松弛 x_u - x_v <= w
    }
    for (ll i = 1; i <= n; i++) {
        G[0].push_back({i, 0});
    }
    bel_ford(0);//关键，必须由0，
    for (ll i = 1; i <= n; i ++) {
        cout << d[i] << " ";
    }
}  
signed main() {
    ll t = 1;//cin >> t;
    while (t--) {
       solve();
    }
}