Leetcode

Leetcode Problems & Solutions

LeetCode Topics

Math

0013-roman-to-integer
0189-rotate-array
0258-add-digits
0326-power-of-three
0342-power-of-four
0380-insert-delete-getrandom-o1
1406-subtract-the-product-and-sum-of-digits-of-an-integer
1426-find-n-unique-integers-sum-up-to-zero
1610-xor-operation-in-an-array
1642-water-bottles
1950-sign-of-the-product-of-an-array
2288-count-operations-to-obtain-zero
2383-add-two-integers
3830-find-closest-person

Array

0001-two-sum
0026-remove-duplicates-from-sorted-array
0027-remove-element
0031-next-permutation
0033-search-in-rotated-sorted-array
0042-trapping-rain-water
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0056-merge-intervals
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0135-candy
0137-single-number-ii
0167-two-sum-ii-input-array-is-sorted
0169-majority-element
0189-rotate-array
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0238-product-of-array-except-self
0274-h-index
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0380-insert-delete-getrandom-o1
0724-find-pivot-index
0940-fruit-into-baskets
1426-find-n-unique-integers-sum-up-to-zero
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value
1950-sign-of-the-product-of-an-array
2876-number-of-employees-who-met-the-target
3242-count-elements-with-maximum-frequency
3251-maximum-area-of-longest-diagonal-rectangle
3740-minimum-distance-between-three-equal-elements-i
3788-maximum-unique-subarray-sum-after-deletion

Two Pointers

0026-remove-duplicates-from-sorted-array
0027-remove-element
0028-find-the-index-of-the-first-occurrence-in-a-string
0031-next-permutation
0042-trapping-rain-water
0080-remove-duplicates-from-sorted-array-ii
0088-merge-sorted-array
0125-valid-palindrome
0167-two-sum-ii-input-array-is-sorted
0189-rotate-array
0287-find-the-duplicate-number
0349-intersection-of-two-arrays
0392-is-subsequence

Sorting

0056-merge-intervals
0088-merge-sorted-array
0169-majority-element
0215-kth-largest-element-in-an-array
0217-contains-duplicate
0274-h-index
0349-intersection-of-two-arrays

String

0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0028-find-the-index-of-the-first-occurrence-in-a-string
0058-length-of-last-word
0125-valid-palindrome
0383-ransom-note
0387-first-unique-character-in-a-string
0392-is-subsequence
0742-to-lower-case
1302-delete-characters-to-make-fancy-string
1784-check-if-binary-string-has-at-most-one-segment-of-ones
1960-check-if-the-sentence-is-pangram

Hash Table

0001-two-sum
0003-longest-substring-without-repeating-characters
0013-roman-to-integer
0169-majority-element
0217-contains-duplicate
0349-intersection-of-two-arrays
0380-insert-delete-getrandom-o1
0383-ransom-note
0387-first-unique-character-in-a-string
0940-fruit-into-baskets
1813-maximum-erasure-value
1960-check-if-the-sentence-is-pangram
3242-count-elements-with-maximum-frequency
3740-minimum-distance-between-three-equal-elements-i
3788-maximum-unique-subarray-sum-after-deletion

Sliding Window

0003-longest-substring-without-repeating-characters
0940-fruit-into-baskets
1586-longest-subarray-of-1s-after-deleting-one-element
1813-maximum-erasure-value

Divide and Conquer

0053-maximum-subarray
0169-majority-element
0215-kth-largest-element-in-an-array

Counting

0169-majority-element
0383-ransom-note
0387-first-unique-character-in-a-string
3242-count-elements-with-maximum-frequency

Dynamic Programming

0042-trapping-rain-water
0045-jump-game-ii
0053-maximum-subarray
0055-jump-game
0121-best-time-to-buy-and-sell-stock
0122-best-time-to-buy-and-sell-stock-ii
0392-is-subsequence
1586-longest-subarray-of-1s-after-deleting-one-element

Greedy

0045-jump-game-ii
0055-jump-game
0122-best-time-to-buy-and-sell-stock-ii
0135-candy
3788-maximum-unique-subarray-sum-after-deletion

Bit Manipulation

0137-single-number-ii
0287-find-the-duplicate-number
0342-power-of-four
1610-xor-operation-in-an-array

Queue

0387-first-unique-character-in-a-string

Counting Sort

0274-h-index

Prefix Sum

0238-product-of-array-except-self
0724-find-pivot-index

Design

0380-insert-delete-getrandom-o1

Randomized

0380-insert-delete-getrandom-o1

Recursion

0326-power-of-three
0342-power-of-four

Binary Search

0033-search-in-rotated-sorted-array
0167-two-sum-ii-input-array-is-sorted
0287-find-the-duplicate-number
0349-intersection-of-two-arrays

String Matching

0028-find-the-index-of-the-first-occurrence-in-a-string

Simulation

0258-add-digits
1642-water-bottles
2288-count-operations-to-obtain-zero

Number Theory

0258-add-digits

Heap (Priority Queue)

0215-kth-largest-element-in-an-array

Quickselect

0215-kth-largest-element-in-an-array

Stack

0042-trapping-rain-water

Monotonic Stack

0042-trapping-rain-water