# Evaluate Reverse Polish Notation (Leetcode 150)

Difficulty: Medium Link: Day 25: May Leetcode Challenge Problem Description Evaluate the value of an arithmetic expression in Reverse Polish Notation. Valid operators are +, -, *, and /. Each…

# To Lower Case (Leetcode 709)

Difficulty: Easy Link: Day 24: May Leetcode Challenge Problem Description Given a string s, return the string after replacing every uppercase letter with the same lowercase letter.…

# Find and Replace Pattern (Leetcode 890)

Difficulty: Medium Link: Day 21: May Leetcode Challenge Problem Description Given a list of strings words and a string pattern, return a list of words[i] that match pattern. You may return the…

# Binary Tree Level Order Traversal (Leetcode 102)

Difficulty : Medium Link: Day 12: May Leetcode Challenge Problem Description Given the root of a binary tree, return the level order traversal of its nodes’ values. (i.e.,…

# Ambiguous Coordinates (Leetcode 816)

Difficulty: Medium Link: Day 13: May Leetcode Challenge Problem Description We had some 2-dimensional coordinates, like “(1, 3)” or “(2, 0.5)”.  Then, we removed all commas, decimal points, and…

# Range Sum Query 2D – Immutable (Leetcode 304)

Difficulty: Medium Link: Day 12: May Leetcode Challenge Problem Description Given a 2D matrix matrix, handle multiple queries of the following type: Calculate the sum of the elements…

# Beautiful Arrangement II (Leetcode 667)

Difficulty : Medium Link : April Leetcoding Challenge 2021: Day 12 Problem Statement Given two integers n and k, you need to construct a list which contains n different positive…