## Find and Replace Pattern

Title: Find and Replace Pattern Source: leetcode.com You have a list of words and a pattern, and you want to know which words in words matches the pattern. A word matches the pattern if there exists a permutation of letters p so that after replacing every letter x in the pattern with p(x), we get ...

Title: Linked List Components Source: leetcode.com We are given head, the head node of a linked list containing unique integer values. We are also given the list G, a subset of the values in the linked list. Return the number of connected components in G, where two values are connected if they appear consecutively in ...

## Increasing Order Search Tree

Title: Increasing Order Search Tree Source: leetcode.com Given a tree, rearrange the tree in in-order so that the leftmost node in the tree is now the root of the tree, and every node has no left child and only 1 right child (Increasing order search tree). Example 1: Input: [5,3,6,2,4,null,8,1,null,null,null,7,9] 5 / \ 3 6 ...

## Find all Anagrams in a String

Title: Custom Sort String Source: leetcode.com Given a string s and a non-empty string p, find all the start indices of p‘s anagrams in s. Strings consists of lowercase English letters only and the length of both strings s and p will not be larger than 20,100. The order of output does not matter. Example ...

## Custom Sort String

Title: Custom Sort String Source: leetcode.com S and T are strings composed of lowercase letters. In S, no letter occurs more than once. S was sorted in some custom order previously. We want to permute the characters of T so that they match the order that S was sorted. More specifically, if x occurs before ...

## Monotonic Array

Title: Monotonic Array Source: leetcode.com An array is monotonic if it is either monotone increasing or monotone decreasing. An array A is monotone increasing if for all i <= j, A[i] <= A[j]. An array A is monotone decreasing if for all i <= j, A[i] >= A[j]. Return true if and only if the ...

## Nth Digit in Whole Numbers

Title: Nth DigitSource: leetcode.com Find the nth digit of the infinite integer sequence 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, … Note: n is positive and will fit within the range of a 32-bit signed integer (n < 231). Python solution The intuition for the solution is thinking about what’s the ...

## Binary Watch Problem

Title: Binary Watch Source: leetcode.com A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59). Each LED represents a zero or one, with the least significant bit on the right. For example, the above binary watch reads “3:25”. Given a ...

## Leaf-Similar trees

Title: Leaf-Similar TreesSource: leetcode.com Consider all the leaves of a binary tree. From left to right order, the values of those leaves form a leaf value sequence. For example, in the given tree above, the leaf value sequence is (6, 7, 4, 9, 8). Two binary trees are considered leaf-similar if their leaf value sequence ...

## Shortest Distance to a Character

Title: Shortest Distance to a CharacterSource: leetcode.com Given a string S and a character C, return an array of integers representing the shortest distance from the character C in the string. Example 1: Input: S = “loveleetcode”, C = ‘e’ Output: [3, 2, 1, 0, 1, 0, 0, 1, 2, 2, 1, 0] Note: 1. ...