Add solution #847

Author: JoshCrozier

README.md

@@ -654,6 +654,7 @@
 844|[Backspace String Compare](./0844-backspace-string-compare.js)|Easy|
 845|[Longest Mountain in Array](./0845-longest-mountain-in-array.js)|Medium|
 846|[Hand of Straights](./0846-hand-of-straights.js)|Medium|
+847|[Shortest Path Visiting All Nodes](./0847-shortest-path-visiting-all-nodes.js)|Hard|
 867|[Transpose Matrix](./0867-transpose-matrix.js)|Easy|
 868|[Binary Gap](./0868-binary-gap.js)|Easy|
 872|[Leaf-Similar Trees](./0872-leaf-similar-trees.js)|Easy|

solutions/0847-shortest-path-visiting-all-nodes.js

@@ -0,0 +1,48 @@
+/**
+ * 847. Shortest Path Visiting All Nodes
+ * https://leetcode.com/problems/shortest-path-visiting-all-nodes/
+ * Difficulty: Hard
+ *
+ * You have an undirected, connected graph of n nodes labeled from 0 to n - 1. You are given an
+ * array graph where graph[i] is a list of all the nodes connected with node i by an edge.
+ *
+ * Return the length of the shortest path that visits every node. You may start and stop at any
+ * node, you may revisit nodes multiple times, and you may reuse edges.
+ */
+
+/**
+ * @param {number[][]} graph
+ * @return {number}
+ */
+var shortestPathLength = function(graph) {
+  const n = graph.length;
+
+  if (n === 1) return 0;
+
+  const allVisited = (1 << n) - 1;
+  const queue = [];
+  const visited = new Set();
+
+  for (let i = 0; i < n; i++) {
+    const initialState = (1 << i);
+    queue.push([i, initialState, 0]);
+    visited.add(`${i},${initialState}`);
+  }
+
+  while (queue.length > 0) {
+    const [node, state, distance] = queue.shift();
+    if (state === allVisited) {
+      return distance;
+    }
+    for (const neighbor of graph[node]) {
+      const newState = state | (1 << neighbor);
+      const key = `${neighbor},${newState}`;
+      if (!visited.has(key)) {
+        visited.add(key);
+        queue.push([neighbor, newState, distance + 1]);
+      }
+    }
+  }
+
+  return -1;
+};