(LeetCode) Maximum Binary Tree

misc/LeetCode/maximumBinaryTree.js

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+/**
+Given an integer array with no duplicates. A maximum tree building on this array is defined as follow:
+
+The root is the maximum number in the array.
+The left subtree is the maximum tree constructed from left part subarray divided by the maximum number.
+The right subtree is the maximum tree constructed from right part subarray divided by the maximum number.
+Construct the maximum tree by the given array and output the root node of this tree.
+
+Example 1:
+Input: [3,2,1,6,0,5]
+Output: return the tree root node representing the following tree:
+
+      6
+    /   \
+   3     5
+    \    /
+     2  0
+       \
+        1
+Note:
+The size of the given array will be in the range [1,1000].
+ */
+
+ /**
+  * Definition for a binary tree node.
+  * function TreeNode(val) {
+  *     this.val = val;
+  *     this.left = this.right = null;
+  * }
+  */
+
+/**
+* @param {number[]} nums
+* @return {TreeNode}
+*/
+var constructMaximumBinaryTree = function(nums) {
+  const stack = [];
+  let c;
+
+  nums.forEach(num => {
+      c = new TreeNode(num);
+
+      while (stack.length && stack[stack.length - 1].val < num) {
+          c.left = stack[stack.length - 1];
+          stack.pop();
+      }
+
+      if (stack.length) {
+          stack[stack.length - 1].right = c;
+      }
+
+      stack.push(c);
+  });
+
+  return stack[0];
+};