DijKstra算法普通+堆优化链式向前星

朴素版本

#include<bits/stdc++.h>
using namespace std;
const int maxn = 10010;
const int inf = 0x3f3f3f3f;
int a[maxn][maxn],dis[maxn],visit[maxn],n,m,s,t;
void init() {
	for(int i = 1; i <= n; i++)
		for(int j = 1; j <= n; j++)
			if(i == j)	a[i][j] = 0;
			else	a[i][j] = inf;
}
void Dij() {
	for(int i = 1; i <= n; i++)	dis[i] = a[s][i];
	dis[s] = 0, visit[s] = 1;
	int minn,su;
	for(int j = 1; j < n; j++) {
		minn = inf, su = -1;
		for(int i = 1; i <= n; i++)
			if(!visit[i] && dis[i] < minn) {
				minn = dis[i];
				su = i;
			}
		visit[su] = 1;
		for(int i = 1; i <= n; i++)
			if(!visit[i])
				dis[i] = min(dis[i],dis[su] + a[su][i]);
	}
	cout << dis[t] <<endl;
}
int main() {
	cin >> n >> m >> s >> t;
	init();
	for(int i = 1; i <= m; i++) {
		int x,y;
		cin >> x >> y;
		cin >> a[x][y];
	}
	Dij();
	return 0;
}

堆优化加链式向前星

#include<bits/stdc++.h>
using namespace std;
const int inf = 0x3f3f3f3f;
const int maxn = 1e5 + 10;
struct edge {
	int to,value,next;
}a[2 * maxn];
struct node {
	int x,pos;
	node(int a,int b) : x(a), pos(b) { }
	bool operator < (const node &t) const {
		return t.x < x;
	}
};
int n, m, visit[maxn], dis[maxn], s, head[maxn],cnt = 1;
void add(int x,int y,int z) {
	a[cnt].to = y;
	a[cnt].value = z;
	a[cnt].next = head[x];
	head[x] = cnt++;
}
void Dij () {
	for(int i = 1; i <= n; i++)	dis[i] = inf;
	dis[s] = 0; visit[s] = 1;
	priority_queue<node>q;
	q.push(node(0,s));
	while(!q.empty()) {
		node temp = q.top();
		q.pop();
		int x = temp.x, pos = temp.pos;
		if(dis[pos] < x) continue;
		for(int i = head[pos]; i; i = a[i].next) {
			if(dis[a[i].to] > dis[pos] + a[i].value) {
				dis[a[i].to] = dis[pos] + a[i].value;
				q.push(node(dis[a[i].to],a[i].to));
			}
		}
	}
	for(int i = 1; i <= n; i++)
		cout << dis[i] << " ";
	cout <<endl;
}
int main() {
	int x, y, z;
	cin >> n >> m >> s;
	for(int i = 0; i < m; i++) {
		cin >> x >> y >> z;
		add(x,y,z);
	}
	Dij();
	return 0;
}