10 docs tagged with "Hard"

Given a non-empty binary tree, find the maximum path sum.

Given a binary tree, return the postorder traversal of its nodes' values.

Say you have an array for which the ith element is the price of a given stock on day i.

There are N children standing in a line. Each child is assigned a rating value.

Given a string S and a string T, count the number of distinct subsequences of S which equals T.

The demons had captured the princess (P) and imprisoned her in the bottom-right corner of a dungeon. The dungeon consists of M x N rooms laid out in a 2D grid. Our valiant knight (K) was initially positioned in the top-left room and must fight his way through the dungeon to rescue the princess.

Given two words word1 and word2, find the minimum number of operations required to convert word1 to word2.

Suppose an array sorted in ascending order is rotated at some pivot unknown to you beforehand.

Given an unsorted integer array, find the smallest missing positive integer.

Given a set of non-overlapping intervals, insert a new interval into the intervals (merge if necessary).