Number of Ways to Arrive at Destination

import java.util.*;

class Solution {
    public int countPaths(int V, int[][] edges) {
        final long MOD = (long) 1e9 + 7;
        List<List<int[]>> adj = new ArrayList<>();
        for (int i = 0; i < V; i++)
            adj.add(new ArrayList<>());

        for (int[] e : edges) {
            int u = e[0], v = e[1], w = e[2];
            adj.get(u).add(new int[] { v, w });
            adj.get(v).add(new int[] { u, w });
        }
        long[] dist = new long[V];
        long[] ways = new long[V];
        Arrays.fill(dist, Long.MAX_VALUE);
        PriorityQueue<long[]> pq = new PriorityQueue<>((a, b) -> Long.compare(a[0], b[0]));
        dist[0] = 0;
        ways[0] = 1;
        pq.add(new long[] { 0, 0 });
        while (!pq.isEmpty()) {
            long[] top = pq.poll();
            long d = top[0];
            int u = (int) top[1];

            if (d > dist[u])
                continue;

            for (int[] nxt : adj.get(u)) {
                int v = nxt[0];
                long w = nxt[1];
                if (dist[v] > dist[u] + w) {
                    dist[v] = dist[u] + w;
                    ways[v] = ways[u];
                    pq.add(new long[] { dist[v], v });
                } else if (dist[v] == dist[u] + w)
                    ways[v] = (ways[v] + ways[u]) % MOD;
            }
        }
        
        return (int) (ways[V - 1] % MOD);
    }
}