[Leetcode] Minimum Height Trees

Use topology sort to find the node(s) residing at center area.

[Leetcode] Task Scheduler

The difficulty of this problem is understanding the pattern of how task and idle are placed.

Description

Given a characters array tasks, representing the tasks a CPU needs to do, where each letter represents a different task. Tasks…

[Leetcode] Minimum Number of Arrows to Burst Balloons

Problems of greedy algorithm are intuitively confusing but surprisingly concise when riddle disclosed.

Description

[Leetcode] Insert Interval

Manipulation for array elements that requires patience.

Description

You are given an array of non-overlapping intervals intervals where intervals[i] = [starti, endi] represent the start and the end of the ith interval and intervals…

[Leetcode] Counting Bits

Dynamic programming is all about finding pattern.

Description

Given an integer n, return an array ans of length n + 1 such that for each i (0 <= i <= n), ans[i] is the number of 1's in the binary representation of i.

[Leetcode] Backspace String Compare

An intuitively challenging paractice for two pointers.

Description

Given two strings s and t, return true if they are equal when both are typed into empty text editors. '#' means a backspace character.

[Leetcode] Longest Increasing Subsequence

Maintain the enlarging maximum along the dp array.

Description

Given an integer array nums, return the length of the longest strictly increasing subsequence.

[Leetcode] K Closest Points to Origin

heapq api in python makes this problem trivial.

Description

[Leetcode] Merge Two Sorted Lists

A classic linked list problem to practice switching attributes from nodes to nodes.

[Leetcode] All Nodes Distance K in Binary Tree

An interesting problem that embodies the idea “a tree is a connected graph with…