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P3371 【模板】单源最短路径(弱化版)

https://www.luogu.com.cn/record/91965144
This commit is contained in:
Baoshuo Ren 2022-10-28 22:15:17 +08:00
parent 4895da7d09
commit cf1446b12c
Signed by: baoshuo
GPG Key ID: 00CB9680AB29F51A

View File

@ -1,43 +1,71 @@
#include <bits/stdc++.h>
#include <iostream>
#include <algorithm>
#include <limits>
#include <queue>
#include <utility>
#include <vector>
using namespace std;
using std::cin;
using std::cout;
const char endl = '\n';
int n, m, s, u, v, w, dist[200005];
vector<pair<int, int>> g[200005];
bool st[200005];
const int N = 1e5 + 5;
void dijkstra() {
memset(dist, 0x3f, sizeof(dist));
int n, m, s;
long long dist[N];
std::vector<std::pair<int, long long>> g[N];
bool vis[N];
void spfa() {
std::fill_n(dist, N, std::numeric_limits<int>::max());
std::queue<int> q;
q.emplace(s);
dist[s] = 0;
priority_queue<pair<int, int>, vector<pair<int, int>>, greater<pair<int, int>>> q;
q.push(make_pair(0, s));
vis[s] = true;
while (!q.empty()) {
auto t = q.top();
int u = q.front();
q.pop();
int tw = t.second;
int td = t.first;
if (st[tw]) continue;
for (auto i : g[tw]) {
int j = i.first;
if (dist[j] > td + i.second) {
dist[j] = td + i.second;
q.push(make_pair(dist[j], j));
vis[u] = false;
for (auto e : g[u]) {
int v = e.first;
long long w = e.second;
if (dist[v] > dist[u] + w) {
dist[v] = dist[u] + w;
if (!vis[v]) {
vis[v] = true;
q.emplace(v);
}
}
}
st[tw] = true;
}
}
int main() {
std::ios::sync_with_stdio(false);
cin.tie(nullptr);
cin >> n >> m >> s;
for (int i = 1; i <= m; i++) {
for (int i = 1, u, v, w; i <= m; i++) {
cin >> u >> v >> w;
g[u].push_back(make_pair(v, w));
g[u].emplace_back(v, w);
}
dijkstra();
spfa();
for (int i = 1; i <= n; i++) {
cout << (dist[i] == 0x3f3f3f3f ? INT_MAX : dist[i]) << ' ';
cout << dist[i] << ' ';
}
cout << endl;
return 0;
}