这两位同学的代码可以作为参考
https://www.acwing.com/solution/content/13602/
https://www.acwing.com/solution/content/23358/

算法基础班–第三章–5.1最短路—朴素Dijkstra算法

算法模板

int g[N][N];
int dist[N];
bool st[N];

int diskstra() {
    memset(dist, 0x3f, sizeof dist);
    dist[1] = 0;
    for (int i = 0; i < n; i++) {
        int t = -1;
        for (int j = 1; j <= n; j++)
            if (!st[j] && (t == -1 || dist[t] > dist[j])) 
                t = j;
        st[t] = true;
        for (int j = 1; j <= n; j++) 
            dist[j] = min(dist[j], dist[t] + g[t][j]);
    }
    if (dist[n] == 0x3f3f3f3f) return -1;
    return dist[n];
}

#include <iostream>
#include <cstring>
#include <algorithm>

using namespace std;

const int N = 510;
int n, m;
int g[N][N];
int dist[N];
bool st[N];

int diskstra() {
    memset(dist, 0x3f, sizeof dist);
    dist[1] = 0;
    for (int i = 0; i < n; i++) {
        int t = -1;
        for (int j = 1; j <= n; j++)
            if (!st[j] && (t == -1 || dist[t] > dist[j])) 
                t = j;
        st[t] = true;
        for (int j = 1; j <= n; j++) 
            dist[j] = min(dist[j], dist[t] + g[t][j]);
    }
    if (dist[n] == 0x3f3f3f3f) return -1;
    return dist[n];
}

int main () {
    scanf("%d%d", &n, &m);
    memset(g, 0x3f, sizeof g);
    while (m--) {
        int a, b, c;
        scanf("%d%d%d", &a, &b, &c);
        g[a][b] = min(g[a][b], c);
    }
    int t = diskstra();
    printf("%d\n", t);
    return 0;
}