Add solution #3108

Author: JoshCrozier

README.md

@@ -929,6 +929,7 @@
 3042|[Count Prefix and Suffix Pairs I](./3042-count-prefix-and-suffix-pairs-i.js)|Easy|
 3066|[Minimum Operations to Exceed Threshold Value II](./3066-minimum-operations-to-exceed-threshold-value-ii.js)|Medium|
 3105|[Longest Strictly Increasing or Strictly Decreasing Subarray](./3105-longest-strictly-increasing-or-strictly-decreasing-subarray.js)|Easy|
+3108|[Minimum Cost Walk in Weighted Graph](./3108-minimum-cost-walk-in-weighted-graph.js)|Hard|
 3110|[Score of a String](./3110-score-of-a-string.js)|Easy|
 3151|[Special Array I](./3151-special-array-i.js)|Easy|
 3160|[Find the Number of Distinct Colors Among the Balls](./3160-find-the-number-of-distinct-colors-among-the-balls.js)|Medium|

solutions/3108-minimum-cost-walk-in-weighted-graph.js

@@ -0,0 +1,58 @@
+/**
+ * 3108. Minimum Cost Walk in Weighted Graph
+ * https://leetcode.com/problems/minimum-cost-walk-in-weighted-graph/
+ * Difficulty: Hard
+ *
+ * There is an undirected weighted graph with n vertices labeled from 0 to n - 1.
+ *
+ * You are given the integer n and an array edges, where edges[i] = [ui, vi, wi] indicates that
+ * there is an edge between vertices ui and vi with a weight of wi.
+ *
+ * A walk on a graph is a sequence of vertices and edges. The walk starts and ends with a vertex,
+ * and each edge connects the vertex that comes before it and the vertex that comes after it.
+ * It's important to note that a walk may visit the same edge or vertex more than once.
+ *
+ * The cost of a walk starting at node u and ending at node v is defined as the bitwise AND of the
+ * weights of the edges traversed during the walk. In other words, if the sequence of edge weights
+ * encountered during the walk is w0, w1, w2, ..., wk, then the cost is calculated as w0 & w1 & w2
+ * & ... & wk, where & denotes the bitwise AND operator.
+ *
+ * You are also given a 2D array query, where query[i] = [si, ti]. For each query, you need to find
+ * the minimum cost of the walk starting at vertex si and ending at vertex ti. If there exists no
+ * such walk, the answer is -1.
+ *
+ * Return the array answer, where answer[i] denotes the minimum cost of a walk for query i.
+ */
+
+/**
+ * @param {number} n
+ * @param {number[][]} edges
+ * @param {number[][]} query
+ * @return {number[]}
+ */
+var minimumCost = function(n, edges, query) {
+  const parent = new Array(n).fill().map((_, i) => i);
+  const costs = new Array(n).fill(2 ** 17 - 1);
+
+  for (const [u, v, w] of edges) {
+    const [p1, p2] = [find(u), find(v)];
+    parent[p1] = p2;
+    costs[p1] = costs[p2] = costs[p1] & costs[p2] & w;
+  }
+
+  for (let i = 0; i < n; i++) {
+    parent[i] = find(i);
+  }
+
+  return query.map(([s, t]) => {
+    if (s === t) return 0;
+    return parent[s] === parent[t] ? costs[parent[s]] : -1;
+  });
+
+  function find(key) {
+    if (parent[key] !== key) {
+      parent[key] = find(parent[key]);
+    }
+    return parent[key];
+  }
+};