图论 - 最短路 - Dijkstra

图论 - 最短路 - Dijkstra

题目链接： https://www.luogu.org/problem/P4779

代码：

#include <bits/stdc++.h>

using namespace std;

const int N = 1e5 + 10;

const int M = 2e5 + 10;

int n, m, s, dis[N];

bool vis[N];

/*<-----Edge_add----->*/

int tot, head[N], to[M], nxt[M], val[M];

void add(int x, int y, int z) {
	to[ ++ tot] = y;
	val[tot] = z;
	nxt[tot] = head[x];
	head[x] = tot;
}

/*<-----Dijkstra----->*/

priority_queue < pair < int, int > > q;

void Dijkstra(int s) {
	memset(vis, 0, sizeof vis);
	memset(dis, 0x3f, sizeof dis);
	dis[s] = 0;
	q.push(make_pair(0, s));
	while (! q.empty()) {
		int now = q.top().second;
		if (vis[now]) {
			q.pop();
			continue ;
		}
		q.pop();
		vis[now] = 1;
		for (int i = head[now]; i; i = nxt[i]) {
			if (dis[to[i]] > dis[now] + val[i]) {
				dis[to[i]] = dis[now] + val[i];
				q.push(make_pair(-dis[to[i]], to[i]));
			}
		}
	}
}

int main() {
	scanf("%d%d%d", &n, &m, &s);
	for (int i = 1; i <= m; i ++ ) {
		int x, y, z;
		scanf("%d%d%d", &x, &y, &z);
		add(x, y, z);
	}
	Dijkstra(s);
	for (int i = 1; i <= n; i ++ ) {
		printf("%d ", dis[i]);
	}
	return 0;
}