链式前向星建图+SPFA求最短路

#include <iostream>
#include <cmath>
#include <cstdlib>
#include <cstring>
#include <climits>
#include <algorithm>
#include <numeric>
#include <utility>
#include <random>
#include <chrono>
#include <string>
#include <vector>
#include <stack>
#include <queue>
#include <set>
#include <map>
#include <unordered_set>
#include <unordered_map>

using namespace std;

using LL = long long;
using ULL = unsigned long long;
using PII = pair<int, int>;
using PIL = pair<int, LL>;
using PLL = pair<LL, LL>;
// const int mod = 1e9 + 7;
// const int mod = 998244353;

inline void quickread() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
}

const int maxn = 1e4 + 5;
const int maxm = 5e5 + 5;
const int inf = INT_MAX;
int n, m, s;
int nne;
int head[maxn];

struct Edge {
    int u, v, w;
    int nxt;
    Edge(int u = 0, int v = 0, int w = 0, int nxt = 0) : 
        u(u), v(v), w(w), nxt(nxt) {};
}edge[maxm];

void init() {
    memset(head, -1, sizeof(head));
    nne = 0;
}

void add_edge(int u, int v, int w) {
    edge[nne] = Edge(u, v, w, head[u]);
    head[u] = nne++;
}



int dis[maxn];
bool vis[maxn];

void build_graph() {
    cin >> n >> m >> s;
    init();
    for (int i = 0; i < m; ++i) {
        int u, v, w;
        cin >> u >> v >> w;
        add_edge(u, v, w);
    }
}

void spfa(int s) {
    for (int i = 1; i <= n; ++i) {
        dis[i] = inf;
        vis[i] = false;
    }
    dis[s] = 0;
    queue<int> q;
    q.push(s);
    vis[s] = true;
    while (!q.empty()) {
        int u = q.front();
        q.pop();
        vis[u] = false;
        for (int e = head[u]; e != -1; e = edge[e].nxt) {
            int v = edge[e].v, w = edge[e].w;
            if (dis[u] + w < dis[v]) {
                dis[v] = dis[u] + w;
                if (!vis[v]) {
                    q.push(v);
                    vis[v] = true;
                }
            }
        } 
    }
}


inline void work() {
    build_graph();
    spfa(s);
    for (int i = 1; i <= n; ++i) 
        cout << dis[i] << " ";
    cout << endl;
}

int main() {
    // freopen(".txt", "r", stdin);
    quickread();
    work();
    return 0;
}