Leetcode

LeetCode Topics

Math

0002-add-two-numbers
0009-palindrome-number
0029-divide-two-integers
0066-plus-one
0069-sqrtx
0268-missing-number
0415-add-strings
0507-perfect-number
0728-self-dividing-numbers
0989-add-to-array-form-of-integer
1037-valid-boomerang
1390-four-divisors
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1440-convert-integer-to-the-sum-of-two-no-zero-integers
1523-count-odd-numbers-in-an-interval-range
1610-xor-operation-in-an-array
1965-sum-of-digits-in-base-k
2083-three-divisors
2238-a-number-after-a-double-reversal
2288-count-operations-to-obtain-zero
2442-count-number-of-distinct-integers-after-reverse-operations
2455-average-value-of-even-numbers-that-are-divisible-by-three
2481-strictly-palindromic-number
2507-number-of-common-factors
2571-find-the-pivot-integer
2608-count-the-digits-that-divide-a-number
2624-difference-between-element-sum-and-digit-sum-of-an-array
2752-sum-multiples
2824-check-if-the-number-is-fascinating
2843-count-symmetric-integers
3055-maximum-odd-binary-number
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3512-minimum-operations-to-make-array-sum-divisible-by-k
3536-maximum-product-of-two-digits
3555-final-array-state-after-k-multiplication-operations-i
3567-convert-date-to-binary
3581-the-two-sneaky-numbers-of-digitville
3606-minimum-element-after-replacement-with-digit-sum
3663-find-the-least-frequent-digit
3768-check-if-digits-are-equal-in-string-after-operations-i
3783-mirror-distance-of-an-integer
3846-minimum-operations-to-make-array-sum-divisible-by-k
3918-check-divisibility-by-digit-sum-and-product
3995-gcd-of-odd-and-even-sums

Linked List

0002-add-two-numbers
0908-middle-of-the-linked-list

Recursion

0002-add-two-numbers

Array

0004-median-of-two-sorted-arrays
0066-plus-one
0121-best-time-to-buy-and-sell-stock
0136-single-number
0169-majority-element
0268-missing-number
0414-third-maximum-number
0442-find-all-duplicates-in-an-array
0500-keyboard-row
0724-find-pivot-index
0804-unique-morse-code-words
0912-sort-an-array
0961-n-repeated-element-in-size-2n-array
0977-squares-of-a-sorted-array
0989-add-to-array-form-of-integer
1037-valid-boomerang
1287-element-appearing-more-than-25-in-sorted-array
1319-unique-number-of-occurrences
1351-count-negative-numbers-in-a-sorted-matrix
1390-four-divisors
1421-find-numbers-with-even-number-of-digits
1426-find-n-unique-integers-sum-up-to-zero
1437-check-if-all-1s-are-at-least-length-k-places-away
1468-check-if-n-and-its-double-exist
1470-shuffle-the-array
1482-how-many-numbers-are-smaller-than-the-current-number
1505-create-target-array-in-the-given-order
1510-find-lucky-integer-in-an-array
1528-kids-with-the-greatest-number-of-candies
1528-shuffle-string
1603-running-sum-of-1d-array
1656-count-good-triplets
1677-matrix-diagonal-sum
1701-average-waiting-time
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1791-richest-customer-wealth
1839-decode-xored-array
1848-sum-of-unique-elements
1929-concatenation-of-array
1944-truncate-sentence
2048-build-array-from-permutation
2102-find-the-middle-index-in-array
2108-find-first-palindromic-string-in-the-array
2116-count-number-of-pairs-with-absolute-difference-k
2137-final-value-of-variable-after-performing-operations
2149-rearrange-array-elements-by-sign
2161-partition-array-according-to-given-pivot
2190-count-common-words-with-one-occurrence
2210-find-target-indices-after-sorting-array
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2274-keep-multiplying-found-values-by-two
2277-count-equal-and-divisible-pairs-in-an-array
2357-make-array-zero-by-subtracting-equal-amounts
2442-number-of-arithmetic-triplets
2442-count-number-of-distinct-integers-after-reverse-operations
2455-average-value-of-even-numbers-that-are-divisible-by-three
2486-most-frequent-even-element
2594-count-pairs-of-similar-strings
2614-maximum-count-of-positive-integer-and-negative-integer
2624-difference-between-element-sum-and-digit-sum-of-an-array
2654-count-the-number-of-vowel-strings-in-range
2714-left-and-right-sum-differences
2727-number-of-senior-citizens
2788-split-strings-by-separator
2847-find-maximum-number-of-string-pairs
2917-count-pairs-whose-sum-is-less-than-target
2977-check-if-a-string-is-an-acronym-of-words
3074-apple-redistribution-into-boxes
3154-maximum-value-of-an-ordered-triplet-i
3176-minimum-sum-of-mountain-triplets-i
3190-find-minimum-operations-to-make-all-elements-divisible-by-three
3226-minimum-number-game
3242-count-elements-with-maximum-frequency
3248-snake-in-matrix
3331-minimum-operations-to-exceed-threshold-value-i
3421-count-pairs-that-form-a-complete-day-i
3446-find-the-number-of-good-pairs-i
3471-minimum-average-of-smallest-and-largest-elements
3476-find-minimum-operations-to-make-all-elements-divisible-by-three
3512-minimum-operations-to-make-array-sum-divisible-by-k
3555-final-array-state-after-k-multiplication-operations-i
3581-the-two-sneaky-numbers-of-digitville
3582-find-indices-of-stable-mountains
3606-minimum-element-after-replacement-with-digit-sum
3663-find-the-least-frequent-digit
3712-sum-of-elements-with-frequency-divisible-by-k
3774-absolute-difference-between-maximum-and-minimum-k-elements
3846-minimum-operations-to-make-array-sum-divisible-by-k
4008-restore-finishing-order
4058-compute-alternating-sum

Hash Table

0169-majority-element
0268-missing-number
0387-first-unique-character-in-a-string
0442-find-all-duplicates-in-an-array
0500-keyboard-row
0782-jewels-and-stones
0804-unique-morse-code-words
0920-uncommon-words-from-two-sentences
0961-n-repeated-element-in-size-2n-array
1264-maximum-number-of-words-you-can-type
1319-unique-number-of-occurrences
1363-greatest-english-letter-in-upper-and-lower-case
1468-check-if-n-and-its-double-exist
1482-how-many-numbers-are-smaller-than-the-current-number
1510-find-lucky-integer-in-an-array
1786-count-the-number-of-consistent-strings
1796-second-largest-digit-in-a-string
1848-sum-of-unique-elements
1960-check-if-the-sentence-is-pangram
2053-check-if-all-characters-have-equal-number-of-occurrences
2116-count-number-of-pairs-with-absolute-difference-k
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2274-keep-multiplying-found-values-by-two
2325-decode-the-message
2357-make-array-zero-by-subtracting-equal-amounts
2377-check-if-number-has-equal-digit-count-and-digit-value
2442-number-of-arithmetic-triplets
2442-count-number-of-distinct-integers-after-reverse-operations
2486-most-frequent-even-element
2594-count-pairs-of-similar-strings
2824-check-if-the-number-is-fascinating
2847-find-maximum-number-of-string-pairs
3146-permutation-difference-between-two-strings
3242-count-elements-with-maximum-frequency
3408-count-the-number-of-special-characters-i
3421-count-pairs-that-form-a-complete-day-i
3446-find-the-number-of-good-pairs-i
3581-the-two-sneaky-numbers-of-digitville
3663-find-the-least-frequent-digit
3712-sum-of-elements-with-frequency-divisible-by-k
3753-maximum-difference-between-even-and-odd-frequency-i
3760-maximum-substrings-with-distinct-start
3871-minimum-deletions-for-at-most-k-distinct-characters
4008-restore-finishing-order

String

0028-find-the-index-of-the-first-occurrence-in-a-string
0058-length-of-last-word
0125-valid-palindrome
0151-reverse-words-in-a-string
0344-reverse-string
0345-reverse-vowels-of-a-string
0387-first-unique-character-in-a-string
0415-add-strings
0500-keyboard-row
0520-detect-capital
0557-reverse-words-in-a-string-iii
0742-to-lower-case
0782-jewels-and-stones
0804-unique-morse-code-words
0917-reverse-only-letters
0920-uncommon-words-from-two-sentences
1205-defanging-an-ip-address
1264-maximum-number-of-words-you-can-type
1363-greatest-english-letter-in-upper-and-lower-case
1528-shuffle-string
1781-check-if-two-string-arrays-are-equivalent
1786-count-the-number-of-consistent-strings
1796-second-largest-digit-in-a-string
1823-determine-if-string-halves-are-alike
1844-replace-all-digits-with-characters
1944-truncate-sentence
1960-check-if-the-sentence-is-pangram
1970-sorting-the-sentence
2053-check-if-all-characters-have-equal-number-of-occurrences
2108-find-first-palindromic-string-in-the-array
2128-reverse-prefix-of-word
2137-final-value-of-variable-after-performing-operations
2168-check-if-numbers-are-ascending-in-a-sentence
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2219-maximum-number-of-words-found-in-sentences
2231-find-first-palindromic-string-in-the-array
2235-capitalize-the-title
2259-remove-digit-from-number-to-maximize-result
2325-decode-the-message
2365-percentage-of-letter-in-string
2377-check-if-number-has-equal-digit-count-and-digit-value
2594-count-pairs-of-similar-strings
2654-count-the-number-of-vowel-strings-in-range
2727-number-of-senior-citizens
2788-split-strings-by-separator
2847-find-maximum-number-of-string-pairs
2886-faulty-keyboard
2977-check-if-a-string-is-an-acronym-of-words
3055-maximum-odd-binary-number
3146-permutation-difference-between-two-strings
3248-snake-in-matrix
3340-check-balanced-string
3408-count-the-number-of-special-characters-i
3567-convert-date-to-binary
3753-maximum-difference-between-even-and-odd-frequency-i
3760-maximum-substrings-with-distinct-start
3768-check-if-digits-are-equal-in-string-after-operations-i
3775-reverse-words-with-same-vowel-count
3794-reverse-string-prefix
3811-reverse-degree-of-a-string
3871-minimum-deletions-for-at-most-k-distinct-characters

Bit Manipulation

0029-divide-two-integers
0136-single-number
0268-missing-number
1610-xor-operation-in-an-array
1786-count-the-number-of-consistent-strings
1839-decode-xored-array
2594-count-pairs-of-similar-strings

Counting

0169-majority-element
0387-first-unique-character-in-a-string
0920-uncommon-words-from-two-sentences
1510-find-lucky-integer-in-an-array
1786-count-the-number-of-consistent-strings
1823-determine-if-string-halves-are-alike
1848-sum-of-unique-elements
2053-check-if-all-characters-have-equal-number-of-occurrences
2116-count-number-of-pairs-with-absolute-difference-k
2177-check-whether-two-strings-are-almost-equivalent
2190-count-common-words-with-one-occurrence
2377-check-if-number-has-equal-digit-count-and-digit-value
2442-count-number-of-distinct-integers-after-reverse-operations
2486-most-frequent-even-element
2594-count-pairs-of-similar-strings
2614-maximum-count-of-positive-integer-and-negative-integer
2654-count-the-number-of-vowel-strings-in-range
3242-count-elements-with-maximum-frequency
3421-count-pairs-that-form-a-complete-day-i
3663-find-the-least-frequent-digit
3712-sum-of-elements-with-frequency-divisible-by-k
3753-maximum-difference-between-even-and-odd-frequency-i
3871-minimum-deletions-for-at-most-k-distinct-characters

Two Pointers

0028-find-the-index-of-the-first-occurrence-in-a-string
0125-valid-palindrome
0151-reverse-words-in-a-string
0344-reverse-string
0345-reverse-vowels-of-a-string
0557-reverse-words-in-a-string-iii
0908-middle-of-the-linked-list
0917-reverse-only-letters
0977-squares-of-a-sorted-array
1468-check-if-n-and-its-double-exist
2108-find-first-palindromic-string-in-the-array
2128-reverse-prefix-of-word
2149-rearrange-array-elements-by-sign
2161-partition-array-according-to-given-pivot
2231-find-first-palindromic-string-in-the-array
2442-number-of-arithmetic-triplets
2481-strictly-palindromic-number
2917-count-pairs-whose-sum-is-less-than-target
3471-minimum-average-of-smallest-and-largest-elements
3775-reverse-words-with-same-vowel-count
3794-reverse-string-prefix

Binary Search

0004-median-of-two-sorted-arrays
0069-sqrtx
0268-missing-number
1351-count-negative-numbers-in-a-sorted-matrix
1468-check-if-n-and-its-double-exist
2210-find-target-indices-after-sorting-array
2614-maximum-count-of-positive-integer-and-negative-integer
2917-count-pairs-whose-sum-is-less-than-target

Divide and Conquer

0004-median-of-two-sorted-arrays
0169-majority-element
0912-sort-an-array

Stack

2128-reverse-prefix-of-word

Simulation

0415-add-strings
1505-create-target-array-in-the-given-order
1701-average-waiting-time
1929-concatenation-of-array
2048-build-array-from-permutation
2137-final-value-of-variable-after-performing-operations
2149-rearrange-array-elements-by-sign
2161-partition-array-according-to-given-pivot
2274-keep-multiplying-found-values-by-two
2288-count-operations-to-obtain-zero
2357-make-array-zero-by-subtracting-equal-amounts
2847-find-maximum-number-of-string-pairs
2886-faulty-keyboard
3226-minimum-number-game
3248-snake-in-matrix
3555-final-array-state-after-k-multiplication-operations-i
3768-check-if-digits-are-equal-in-string-after-operations-i
3775-reverse-words-with-same-vowel-count
3811-reverse-degree-of-a-string
4058-compute-alternating-sum

String Matching

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

Dynamic Programming

0121-best-time-to-buy-and-sell-stock

Matrix

1351-count-negative-numbers-in-a-sorted-matrix
1677-matrix-diagonal-sum
1791-richest-customer-wealth

Sorting

0169-majority-element
0268-missing-number
0414-third-maximum-number
0442-find-all-duplicates-in-an-array
0912-sort-an-array
0977-squares-of-a-sorted-array
1468-check-if-n-and-its-double-exist
1482-how-many-numbers-are-smaller-than-the-current-number
1970-sorting-the-sentence
2210-find-target-indices-after-sorting-array
2274-keep-multiplying-found-values-by-two
2357-make-array-zero-by-subtracting-equal-amounts
2917-count-pairs-whose-sum-is-less-than-target
3074-apple-redistribution-into-boxes
3226-minimum-number-game
3471-minimum-average-of-smallest-and-largest-elements
3536-maximum-product-of-two-digits
3774-absolute-difference-between-maximum-and-minimum-k-elements
3871-minimum-deletions-for-at-most-k-distinct-characters

Prefix Sum

0724-find-pivot-index
1603-running-sum-of-1d-array
2102-find-the-middle-index-in-array
2571-find-the-pivot-integer
2714-left-and-right-sum-differences

Counting Sort

0912-sort-an-array
1482-how-many-numbers-are-smaller-than-the-current-number

Heap (Priority Queue)

0912-sort-an-array
2357-make-array-zero-by-subtracting-equal-amounts
3226-minimum-number-game
3555-final-array-state-after-k-multiplication-operations-i

Enumeration

1363-greatest-english-letter-in-upper-and-lower-case
1656-count-good-triplets
2083-three-divisors
2259-remove-digit-from-number-to-maximize-result
2442-number-of-arithmetic-triplets
2507-number-of-common-factors
2843-count-symmetric-integers

Greedy

2259-remove-digit-from-number-to-maximize-result
2357-make-array-zero-by-subtracting-equal-amounts
3055-maximum-odd-binary-number
3074-apple-redistribution-into-boxes
3871-minimum-deletions-for-at-most-k-distinct-characters

Number Theory

2083-three-divisors
2507-number-of-common-factors
3768-check-if-digits-are-equal-in-string-after-operations-i
3995-gcd-of-odd-and-even-sums

Brainteaser

2481-strictly-palindromic-number

Queue

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

Combinatorics

3768-check-if-digits-are-equal-in-string-after-operations-i

Merge Sort

0912-sort-an-array

Bucket Sort

0912-sort-an-array

Radix Sort

0912-sort-an-array

Geometry

1037-valid-boomerang