最短路-Dijkstra算法-优快云博客

本文链接：https://blog.youkuaiyun.com/seanbill/article/details/109208208

本文详细介绍了使用Dijkstra算法解决洛谷P4779问题的具体实现过程，通过C++代码展示了如何构建图结构，并利用优先队列实现最短路径算法，最终输出从指定起点到各顶点的最短距离。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

洛谷 p4779

#include <iostream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;

const int MAXN = 1e5+7 ,MAXM = 500007;
const int INF = 0x7fffffff;
struct Edge {
	int  to, w,next;
	Edge() : to(0), w(0) ,next(0){}
}nodes[MAXM];

int heads[MAXN ] = {0}, d[MAXN] = { 0 }, visit[MAXN] = { 0 }, nCount = 0, n = 0, m = 0, s = 0;

void AddEdge(int from, int to, int widght) {
	nodes[++nCount].to = to;
	nodes[nCount].w = widght;
	nodes[nCount].next = heads[from];
	heads[from] = nCount;
}

void Dijkstra(int s) {
	
	for (int i = 1; i <= n; ++i) d[i] = INF;

	d[s] = 0;

	priority_queue<pair<int, int> ,vector<pair<int,int> > ,greater<pair<int,int> > > que;

	que.push(make_pair(0, s));
	while (!que.empty()) {
		pair<int, int> temp = que.top(); que.pop();
		int u = temp.second;
		if (visit[u]) continue;;
		visit[u] = true;

		for (int i = heads[u]; i; i = nodes[i].next) {
			int v = nodes[i].to;
			if (d[v] > d[u] + nodes[i].w) {
				d[v] = d[u] + nodes[i].w;
				if(!visit[v])
					que.push( make_pair( d[v], v ) );
			}
		}
	}
}
int main()
{
	cin >> n >> m >> s;
	int a, b, c;
	for (int i = 1; i <= m; ++i) {
		cin >> a >> b >> c;
		AddEdge(a, b, c);
	}
	Dijkstra(s);

	for (int i = 1; i <= n; ++i) {
		cout << d[i] << " ";
	}
	return 0;
}