Siqi Liu Yosgi

Time: 30 minutes The idea is to first use the time complexity of On to count, and then solve it using the minimum heap method class Heap { constructor(list, compare = (a, b) => a - b) { this.left = …

Time: 10 minutes const swap = function (arr,i,j) { [arr[i],arr[j]] = [arr[j],arr[i]] } class MaxHeap { constructor() { this.count = 0 this.data = new Array(this.count + 1) } shiftUp(k) { // Put the …

Time: Read the answer Since it is a pile exercise, it must be closer to the idea of pile Since we only want the median, there is no need to sort all the numbers. You can use two heaps, a maximum heap …

Time: Refer to the answer After reading the title, the first thing that comes to mind is that dp cannot escape But writing the conversion equation requires some skill Observe that dp[1][1] = …

Time: 10 minutes A simple question shouldn’t ask me to write the maximum heap by hand. const swap = function (arr,i,j) { [arr[i],arr[j]] = [arr[j],arr[i]] } class MaxHeap { constructor() { this.count …

Time: 60 minutes I was misled by the depth of the question and thought that the calculation depth should be done from top to bottom. In fact, it can be done from bottom to top. If the left and right …

Time: 10 minutes Solve by using the property of pre-order traversal of binary tree var minDiffInBST = function(root) { var min = Infinity var pre = null var dfs = function (root) { if (!root) return …

Time: 10 minutes The preorder is calculated from top to bottom, there is nothing much to say Converting binary to decimal is quite difficult, so I just parseInt(path, 2) var sumRootToLeaf = …

Post-order traversal approach to delete target-valued leaf nodes using a dummy root.

Notes on counting good nodes in a binary tree using DFS with a running max.