Day 1 |
Add digits |
π’ Easy |
Math , number theory |
Day 2 |
Count symmetric integers |
π’ Easy |
math, enumeration |
Day 3 |
Happy Number |
π’ Easy |
Math , two pointer ,HashΒ Table |
Day 4 |
Valid perfect square |
π’ Easy |
Math, Binary search |
Day 5 |
Count total number of colored cells |
π‘ medium |
Math |
Day 6 |
Factorial trailing zeroes |
π‘ medium |
Math |
Day 7 |
Find Sum of Encrypted Integers |
π’ Easy |
Array , Math |
Day 8 |
https://www.geeksforgeeks.org/problems/gcd-of-two-numbers3459/1 |
π’ Easy |
Math |
Day 9 |
https://leetcode.com/problems/max-consecutive-ones/ |
π’ Easy |
Array |
Day 10 |
https://leetcode.com/problems/check-if-array-is-sorted-and-rotated/ |
π’ Easy |
Array |
Day 11 |
https://leetcode.com/problems/two-sum/ |
π’ Easy |
Array |
Day 12 |
https://leetcode.com/problems/plus-one/ |
π’ Easy |
Array, Math |
Day 13 |
https://leetcode.com/problems/find-target-indices-after-sorting-array |
π’ Easy |
Array, Binary Search, Sorting |
Day 14 |
Best time to buy and sell stocks |
π’ Easy |
Array |
Day 15 |
Set Matrix zeros |
π‘ Medium |
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Array, Hash Table, matrix |
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Day 16 |
Max sum of a pair with equal sum of digits |
π‘ Medium |
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Array |
Hash Table |
Sorting |
Heap (Priority Queue) |
Day 17 |
3105. Longest Strictly Increasing or Strictly Decreasing Subarray |
π’ Easy |
Array |
Day 18 |
Maximum Subarray |
π‘ Medium |
ArrayDivide and ConquerDynamic Programming |
Day 19 |
Binary subarrays with sum |
π‘ Medium |
Array Hash TableSliding WindowPrefix Sum |
Day 20 |
Count number of nice subarrays |
π‘ Medium |
Array |
Day 21 |
https://leetcode.com/problems/product-of-array-except-self/ |
π‘ Medium |
Array, Prefix Sum |
Day 22 |
https://leetcode.com/problems/zero-array-transformation-i |
π‘ Medium |
Array, prefix sum |
Day 23 |
https://leetcode.com/problems/apply-operations-to-an-array |
π‘ Medium |
Array, Two Pointers, Simulation |
Day 24 |
https://leetcode.com/problems/find-peak-element |
π‘ Medium |
Array, Binary search |
Day 25 |
https://leetcode.com/problems/single-element-in-a-sorted-array/ |
π‘ Medium |
Array, Binary search |
Day 26 |
https://leetcode.com/problems/find-the-smallest-divisor-given-a-threshold |
π‘ Medium |
Array, Binary search |
Day 27 |
https://leetcode.com/problems/spiral-matrix/ |
π‘ Medium |
Array |
Day 28 |
https://leetcode.com/problems/length-of-last-word/ |
π’ easy |
string |
Day 29 |
https://leetcode.com/problems/is-subsequence/ |
π’ easy |
String , Two Pointers, Dynamic Problem |
Day 30 |
https://leetcode.com/problems/remove-all-occurrences-of-a-substring/description/ |
π‘ Medium |
String |
Day 31 |
https://leetcode.com/problems/reverse-string/ |
π’ easy |
String , Two Pointers |
Day 32 |
https://leetcode.com/problems/first-unique-character-in-a-string/ |
π’ easy |
Hash Table |
Day 33 |
https://leetcode.com/problems/jewels-and-stones/ |
π’ easy |
String , Hash table |
Day 34 |
https://leetcode.com/problems/reverse-words-in-a-string-iii/ |
π’ easy |
Two Pointers |
Day 35 |
https://leetcode.com/problems/longest-common-prefix/ |
π’ easy |
String |
Day 36 |
https://leetcode.com/problems/rotate-string/ |
π’ easy |
String , String Matching |
Day 37 |
https://leetcode.com/problems/isomorphic-strings/description/ |
π’ easy |
String , Hash Table |
Day 38 |
https://leetcode.com/problems/valid-anagram/ |
π‘ Medium |
String , Hash Table |
Day 39 |
https://leetcode.com/problems/valid-parentheses/description/ |
π’ easy |
String , Stack |
Day 40 |
https://leetcode.com/problems/reverse-linked-list/ |
π’ easy |
LinkedList |
Day 41 |
https://leetcode.com/problems/middle-of-the-linked-list/ |
π’ easy |
LinkedList, two -pointer |
Day 41 |
https://leetcode.com/problems/middle-of-the-linked-list/ |
π’ easy |
LinkedList, two -pointer |
Day 42 |
https://leetcode.com/problems/linked-list-cycle/ |
π’ easy |
LinkedList |
Day 43 |
https://leetcode.com/problems/palindrome-linked-list/ |
π‘ Medium |
LinkedList, Two Pointers |
Day 44 |
https://leetcode.com/problems/remove-nth-node-from-end-of-list/ |
π‘ Medium |
LinkedList, Two Pointers |
Day 45 |
https://leetcode.com/problems/remove-duplicates-from-sorted-list |
π’ easy |
LinkedList |
Day 46 |
https://leetcode.com/problems/remove-linked-list-elements |
π‘ Medium |
LinkedList |
Day 47 |
https://leetcode.com/problems/odd-even-linked-list/ |
π‘ Medium |
Linked List manipulation / reordering |
Day 48 |
https://leetcode.com/problems/single-number/ |
π’ Easy |
Bit Manipulation, also relates to Hashing and Array |
Day 49 |
https://leetcode.com/problems/number-of-1-bits/ |
π’ Easy |
Bit Manipulation , Binary Representation |
Day 50 |
https://leetcode.com/problems/power-of-two/ |
π’ Easy |
Bit Manipulation |
Day 51 |
Missing Number |
Easy |
Bit Manipulation, Array, Math |
Day 52 |
Power of three |
Easy |
Math Recursion |
Day 53 |
Reverse Bits |
Easy |
Bit Manipulation , Divide and conquer |
Day 54 |
Sum of two integers |
Medium |
Bit Manipulation |
Day 55 |
implement-stack-using-arrays |
π’ Easy |
Stack |
Day 56 |
maximum-nesting-depth-of-the-parentheses |
π’ Easy |
String and Stack |
Day 57 |
min-stack |
π‘ Medium |
Stack and Design |
Day 58 |
final-prices-with-a-special-discount-in-a-shop |
π’ Easy |
Array and Stack |
Day 59 |
https://leetcode.com/problems/next-greater-element-i/description/ |
π’ Easy |
Array , Hash table and Stack |
Day 60 |
https://leetcode.com/problems/next-greater-element-ii/description/ |
π‘ Medium |
Array , Stack and Monotonic Stack |
Day 61 |
https://leetcode.com/problems/asteroid-collision/description/ |
π‘ Medium |
Array , Stack and Simulation |
Day 62 |
https://leetcode.com/problems/implement-stack-using-queues/description/ |
π’ Easy |
Stack and Queue |
Day 63 |
https://leetcode.com/problems/implement-queue-using-stacks/description/ |
π’ Easy |
Queue and Stacks |
Day 64 |
https://leetcode.com/problems/last-stone-weight/description/ |
π’ Easy |
Array and Queue |
Day 65 |
https://leetcode.com/problems/kth-largest-element-in-an-array/ |
π’ Easy |
Array and Queue |
Day 66 |
https://leetcode.com/problems/minimum-operations-to-exceed-threshold-value-ii |
π‘ Medium |
Array, Priority Queue, |
Day 67 |
https://leetcode.com/problems/design-twitter/description/ |
π‘ Medium |
HashTable, LinkedList, Priority Queue |
Day 68 |
https://leetcode.com/problems/merge-k-sorted-lists/description/ |
Hard |
LinkedList, MergeSort, PriorityQueue |
Day 69 |
https://leetcode.com/problems/maximum-depth-of-binary-tree |
Easy |
Tree, DFS, BFS |
Day 70 |
https://leetcode.com/problems/same-tree |
Easy |
Tree, DFS, BFS |
Day 71 |
https://leetcode.com/problems/invert-binary-tree |
Easy |
Tree, DFS, BFS |
Day 72 |
https://leetcode.com/problems/minimum-depth-of-binary-tree |
Easy |
Tree, DFS, BFS |
Day 73 |
https://leetcode.com/problems/path-sum/description/ |
Easy |
Tree, DFS, BFS |
day 74 |
https://leetcode.com/problems/balanced-binary-tree/ |
Easy |
Tree, DFS |
Day 75 |
https://leetcode.com/problems/binary-tree-maximum-path-sum/description/ |
Hard |
DP, Tree, DFS |
Day 76 |
https://leetcode.com/problems/construct-binary-tree-from-preorder-and-inorder-traversal/description/ |
Medium |
ArrayHash TableDivide and ConquerTreeBinary Tree |
Day 77 |
https://leetcode.com/problems/path-sum-ii/description/ |
Medium |
Tree, DFS, BFS |
Day 78 |
https://leetcode.com/problems/path-sum-ii/description/ |
Medium |
Backtracking, Tree, DFS |
Day 79 |
http://leetcode.com/problems/lowest-common-ancestor-of-a-binary-search-tree/ |
Medium |
Tree, DFS, BFS |
Day 80 |
https://leetcode.com/problems/flood-fill/description/ |
Easy |
Array, DFS, BFS, Matrix |
day 81 |
https://leetcode.com/problems/number-of-provinces/description/ |
Medium |
DFS, BFS, graph |
Day 82 |
https://leetcode.com/problems/rotting-oranges/description/ |
Medium |
Array, BFS, Matrix |
Day 83 |
https://leetcode.com/problems/number-of-islands/ |
Medium |
Array, DFS, BFS, Matrix |
Day 84 |
https://leetcode.com/problems/find-the-town-judge |
Easy |
Array, HashTable, Graph |