Posts

Leetcode 216: Combination Sum III

Posted on July 6, 2018

Question Find all possible combinations of k numbers that add up to a number n, given that only numbers from 1 to 9 can be used and each combination should be a unique set of numbers. [Read More]
Tags:
- Leetcode
- Backtracking
Leetcode 211: Add and Search Word - Data structure design

Posted on July 6, 2018

Question Design a data structure that supports the following two operations: [Read More]
Tags:
- Leetcode
Leetcode 215: Kth Largest Element in an Array

Posted on July 4, 2018

Question Find the kth largest element in an unsorted array. Note that it is the kth largest element in the sorted order, not the kth distinct element. [Read More]
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Leetcode 209: Minimum Size Subarray Sum

Posted on July 4, 2018

Question Given an array of n positive integers and a positive integer s, find the minimal length of a contiguous subarray of which the sum ≥ s. If there isn’t one, return 0 instead. [Read More]
Tags:
- Leetcode
- SlidingWindow
Leetcode 208: Implement Trie (Prefix Tree)

Posted on July 4, 2018

Question Implement a trie with insert, search, and startsWith methods. [Read More]
Tags:
- Leetcode
Leetcode 205: Isomorphic Strings

Posted on July 4, 2018

Question Given two strings s and t, determine if they are isomorphic. [Read More]
Tags:
- Leetcode
Leetcode 204: Count Primes

Posted on July 4, 2018

Question Count the number of prime numbers less than a non-negative number, n. [Read More]
Tags:
- Leetcode
Leetcode 202: Happy Number

Posted on July 4, 2018

Question Write an algorithm to determine if a number is “happy”. [Read More]
Tags:
- Leetcode
Leetcode 201: Bitwise AND of Numbers Range

Posted on July 3, 2018

Question Given a range [m, n] where 0 <= m <= n <= 2147483647, return the bitwise AND of all numbers in this range, inclusive. [Read More]
Tags:
- Leetcode
Leetcode 186: Reverse Words in a String II

Posted on July 3, 2018

Question Given an input string , reverse the string word by word. [Read More]
Tags:
- Leetcode
Leetcode 187: Repeated DNA Sequences

Posted on July 3, 2018

Question All DNA is composed of a series of nucleotides abbreviated as A, C, G, and T, for example: “ACGAATTCCG”. When studying DNA, it is sometimes useful to identify repeated sequences within the DNA. [Read More]
Tags:
- Leetcode
Leetcode 189: Rotate Array

Posted on July 3, 2018

Question Given an array, rotate the array to the right by k steps, where k is non-negative. [Read More]
Tags:
- Leetcode
Leetcode 190: Reverse Bits

Posted on July 3, 2018

Question Reverse bits of a given 32 bits unsigned integer. [Read More]
Tags:
- Leetcode
Leetcode 191: Number of 1 Bits

Posted on July 3, 2018

Question Write a function that takes an unsigned integer and returns the number of ‘1’ bits it has (also known as the Hamming weight). [Read More]
Tags:
- Leetcode
Leetcode 199: Binary Tree Right Side View

Posted on July 3, 2018

Question Given a binary tree, imagine yourself standing on the right side of it, return the values of the nodes you can see ordered from top to bottom. [Read More]
Tags:
- Leetcode

Leetcode 216: Combination Sum III

Leetcode 211: Add and Search Word - Data structure design

Leetcode 215: Kth Largest Element in an Array

Leetcode 209: Minimum Size Subarray Sum

Leetcode 208: Implement Trie (Prefix Tree)

Leetcode 205: Isomorphic Strings

Leetcode 204: Count Primes

Leetcode 202: Happy Number

Leetcode 201: Bitwise AND of Numbers Range

Leetcode 186: Reverse Words in a String II

Leetcode 187: Repeated DNA Sequences

Leetcode 189: Rotate Array

Leetcode 190: Reverse Bits

Leetcode 191: Number of 1 Bits

Leetcode 199: Binary Tree Right Side View