Leetcode 1928. minimum cost of reaching the destination within the specified time

LeetCode 1928. The minimum cost of reaching the destination within the specified time

Two dimensional shortest path

typedef pair<int, int> PII;
#define x first
#define y second
const int N = 1010, M = 2010, INF = 0x3f3f3f3f;
class Solution {
    
public:
    int h[N], w[M], e[M], ne[M], idx = 0;
    int dist[N][N]; // Starting point i, Spend time on j Minimum toll of 
    bool st[N][N] = {
    false};
    void add(int a, int b, int c)
    {
    
        e[idx] = b, ne[idx] = h[a], w[idx] = c, h[a] = idx ++;
    }
    void spfa(int m, vector<int>& pf)
    {
    
        memset(dist, 0x3f, sizeof dist);
        queue<PII> q;
        q.push({
    0, 0});
        dist[0][0] = pf[0];
        st[0][0] = true;
        while(!q.empty())
        {
    
            auto t = q.front();
            q.pop();
            st[t.x][t.y] = false;
            for(int i = h[t.x]; ~i; i = ne[i])
            {
    
                int x = e[i], y = t.y + w[i];
                if(y > m) continue;
                if(dist[x][y] > dist[t.x][t.y] + pf[x])
                {
    
                    dist[x][y] = dist[t.x][t.y] + pf[x];
                    if(!st[x][y])
                    {
    
                        q.push({
    x, y});
                        st[x][y] = true;
                    }
                }
            }
        }
    }
    int minCost(int maxTime, vector<vector<int>>& edges, vector<int>& pf) {
    
        memset(h, -1, sizeof h);
        for(auto&& e : edges)
        {
    
            int a = e[0], b = e[1], c = e[2];
            add(a, b, c), add(b, a, c);
        }
        spfa(maxTime, pf);
        int n = pf.size();
        int res = INF;
        for(int i = 0; i <= maxTime; i ++)
        {
    
            res = min(res, dist[n - 1][i]);
        }
        if(res == INF) return -1;
        else return res;
    }
};