class Solution {
public:

    void dijkstra(vector<vector<int>>& w, int k, int n,vector<bool>& vis,vector<int>& dist) {
        // 只有起点k最短距离为 0
        dist[k] = 0;
        // 迭代 n 次, n表示一共n个节点
        for (int p = 1; p <= n; p++) {
            // 每次找到「最短距离最小」且「未被更新」的点 t
            int t = -1;
            for (int i = 1; i <= n; i++) {
                if (!vis[i] && (t == -1 || dist[i] < dist[t])) 
                    t = i;
            }
            // 标记点 t 为已更新
            vis[t] = true;
            // 用点 t 的「最小距离」更新其他点
            for (int i = 1; i <= n; i++) {
                dist[i] = min(dist[i], dist[t] + w[t][i]);
                // cout<<i<<":" <<dist[i]<<endl; 
            }
        }
    }
    int networkDelayTime(vector<vector<int>>& times, int n, int k) {
        // 数组的长度根据题目每个参数的最大值进行设定
        vector<vector<int>> w(101,vector<int>(101));
        int INF = 0x3f3f3f3f;
        // 起始先将所有的点标记为「未更新」和「距离为正无穷」 expected parameter declarator
        vector<bool> vis = vector<bool>(101, false);
        vector<int> dist = vector<int>(101, INF);
        // 初始化邻接矩阵
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= n; j++) {
                w[i][j] = w[j][i] = i == j ? 0 : INF;
            }
        }
        // 存图
        for (auto t : times) {
            int u = t[0], v = t[1], c = t[2];
            // cout<<"val:" <<u<<" "<<v<<" "<<c<<endl; 
            w[u][v] = c;
        }
        dijkstra(w,k,n,vis,dist);
        int res = 0;
        for(int i = 1; i <= n; i++){
            res = max(res, dist[i]);
        }
        return res > INF / 2 ? -1 : res;
    }
};