Add solution #1145

Author: JoshCrozier

README.md

@@ -1,4 +1,4 @@
-# 1,151 LeetCode solutions in JavaScript
+# 1,152 LeetCode solutions in JavaScript
 
 [https://leetcodejavascript.com](https://leetcodejavascript.com)
 
@@ -899,6 +899,7 @@
 1140|[Stone Game II](./solutions/1140-stone-game-ii.js)|Medium|
 1143|[Longest Common Subsequence](./solutions/1143-longest-common-subsequence.js)|Medium|
 1144|[Decrease Elements To Make Array Zigzag](./solutions/1144-decrease-elements-to-make-array-zigzag.js)|Medium|
+1145|[Binary Tree Coloring Game](./solutions/1145-binary-tree-coloring-game.js)|Medium|
 1161|[Maximum Level Sum of a Binary Tree](./solutions/1161-maximum-level-sum-of-a-binary-tree.js)|Medium|
 1189|[Maximum Number of Balloons](./solutions/1189-maximum-number-of-balloons.js)|Easy|
 1200|[Minimum Absolute Difference](./solutions/1200-minimum-absolute-difference.js)|Easy|

solutions/1145-binary-tree-coloring-game.js

@@ -0,0 +1,60 @@
+/**
+ * 1145. Binary Tree Coloring Game
+ * https://leetcode.com/problems/binary-tree-coloring-game/
+ * Difficulty: Medium
+ *
+ * Two players play a turn based game on a binary tree. We are given the root of this binary tree,
+ * and the number of nodes n in the tree. n is odd, and each node has a distinct value from 1 to n.
+ *
+ * Initially, the first player names a value x with 1 <= x <= n, and the second player names a value
+ * y with 1 <= y <= n and y != x. The first player colors the node with value x red, and the second
+ * player colors the node with value y blue.
+ *
+ * Then, the players take turns starting with the first player. In each turn, that player chooses
+ * a node of their color (red if player 1, blue if player 2) and colors an uncolored neighbor of
+ * the chosen node (either the left child, right child, or parent of the chosen node.)
+ *
+ * If (and only if) a player cannot choose such a node in this way, they must pass their turn. If
+ * both players pass their turn, the game ends, and the winner is the player that colored more
+ * nodes.
+ *
+ * You are the second player. If it is possible to choose such a y to ensure you win the game,
+ * return true. If it is not possible, return false.
+ */
+
+/**
+ * Definition for a binary tree node.
+ * function TreeNode(val, left, right) {
+ *     this.val = (val===undefined ? 0 : val)
+ *     this.left = (left===undefined ? null : left)
+ *     this.right = (right===undefined ? null : right)
+ * }
+ */
+/**
+ * @param {TreeNode} root
+ * @param {number} n
+ * @param {number} x
+ * @return {boolean}
+ */
+var btreeGameWinningMove = function(root, n, x) {
+  let leftCount = 0;
+  let rightCount = 0;
+
+  countNodes(root);
+
+  const parentCount = n - leftCount - rightCount - 1;
+  const maxRegion = Math.max(parentCount, leftCount, rightCount);
+
+  return maxRegion > n / 2;
+
+  function countNodes(node) {
+    if (!node) return 0;
+    const left = countNodes(node.left);
+    const right = countNodes(node.right);
+    if (node.val === x) {
+      leftCount = left;
+      rightCount = right;
+    }
+    return left + right + 1;
+  }
+};