Coding Problems

Return level order traversal of binary tree nodes

Check if parentheses in string are valid

Design class to find median of numbers from data stream

Return k most frequent elements

Find kth largest element in unsorted array

Insert new interval into sorted list of non-overlapping intervals

Merge all overlapping intervals

Find minimum number of rooms needed for all meetings

Calculate how much water can be trapped between bars

Find two lines that form container with most water

Find minimum element in rotated sorted array

Search for target in rotated sorted array

Calculate time until all fresh oranges are rotten (BFS)

Count number of islands in 2D grid (1=land, 0=water)

Check if you can finish all courses given prerequisites

Determine if string can be segmented into dictionary words

Find the longest substring that is a palindrome

Group words that are anagrams together

Find smallest substring containing all characters of pattern

Find length of longest substring without repeating characters