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1 |
Two Sum |
Solution ⭐ |
O(n) |
O(n) |
Easy |
Array, Hash Table |
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2 |
Add Two Numbers |
Solution |
O(n) |
O(1) |
Medium |
Linked List, Math |
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3 |
Longest Substring Without Repeating Characters |
Solution ⭐ |
O(n) |
O(n) |
Medium |
Hash Table, Two Pointers, String |
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7 |
Reverse Integer |
Solution ⭐ |
O(n) |
O(1) |
Easy |
Math |
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9 |
Palindrome Number |
Solution |
O(1) |
O(1) |
Easy |
Math |
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11 |
Container With Most Water |
Solution ⭐ |
O(n) |
O(1) |
Medium |
Array, Two Pointers |
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12 |
Integer to Roman |
Solution ⭐ |
O(1) |
O(1) |
Medium |
Math, String |
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13 |
Roman to Integer |
Solution ⭐ |
O(n) |
O(1) |
Medium |
Math, String |
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14 |
Longest Common Prefix |
Solution |
O(n^2) |
O(1) |
Easy |
String |
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19 |
Remove Nth Node From End of List |
Solution |
O(n) |
O(1) |
Medium |
Linked List, Two Pointers |
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20 |
Valid Parentheses |
Solution |
O(n) |
O(n) |
Easy |
String, Stack |
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21 |
Merge Two Sorted Lists |
Solution |
O(n) |
O(n) |
Easy |
Linked List |
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24 |
Swap Nodes in Pairs |
Solution |
O(n) |
O(1) |
Medium |
Linked List |
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25 |
Reverse Nodes in k-Group |
Solution |
O(n) |
O(1) |
Hard |
Linked List |
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26 |
Remove Duplicates from Sorted Array |
Solution |
O(n) |
O(1) |
Easy |
Array, Two Pointers |
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27 |
Remove Element |
Solution |
O(n) |
O(1) |
Easy |
Array, Two Pointers |
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35 |
Search Insert Position |
Solution |
O(n) |
O(1) |
Easy |
Array, Binary Search |
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43 |
Multiply Strings |
Solution |
O(1) |
O(1) |
Medium |
Math, String |
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50 |
Pow(x,n) |
Solution |
O(logn) |
O(1) |
Medium |
Math, Binary Search |
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53 |
Maximum Subarray |
Solution |
O(n) |
O(1) |
Easy |
Array, Divide and Conquer, Dynamic Programming |
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61 |
Plus One |
Solution |
O(n) |
O(1) |
Easy |
Array, Math |
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65 |
Valid Number |
Solution |
O(1) |
O(1) |
Hard |
Math, String |
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73 |
Set Matrix Zeroes |
Solution |
O(n^2) |
O(1) |
Medium |
Array |
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78 |
Subsets |
Solution |
O(n^2) |
O(n^2) |
Medium |
Array, Backtracking, Bit Manipulation |
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83 |
Remove Duplicates from Sorted List |
Solution |
O(n) |
O(1) |
Easy |
Linked List |
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89 |
Gray Code |
Solution |
O(n^2) |
O(n) |
Medium |
Backtracking |
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118 |
Pascal's Triangle |
Solution |
O(n^2) |
O(1) |
Easy |
Array |
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119 |
Pascal's Triangle II |
Solution |
O(n^2) |
O(k) |
Easy |
Array |
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121 |
Best Time to Buy and Sell Stock |
Solution |
O(n) |
O(1) |
Easy |
Array, Dynamic Programming |
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125 |
Valid Palindrome |
Solution |
O(1) |
O(1) |
Easy |
Two Pointers, String |
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136 |
Single Number |
Solution |
O(n) |
O(1) |
Easy |
Hash Table, Bit Manipulation |
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141 |
Linked List Cycle |
Solution |
O(n) |
O(1) |
Easy |
Linked List, Two Pointers |
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142 |
Linked List Cycle II |
Solution |
O(n) |
O(n) |
Medium |
Linked List, Two Pointers |
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160 |
Intersection of Two Linked Lists |
Solution |
O(n) |
O(n) |
Easy |
Linked List |
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167 |
Two Sum II - Input array is sorted |
Solution |
O(n) |
O(1) |
Easy |
Array, Two Pointers, Binary Search |
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169 |
Majority Element |
Solution |
O(n) |
O(1) |
Easy |
Array, Divide and Conquer, Bit Manipulation |
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172 |
Factorial Trailing Zeroes |
Solution |
O(n) |
O(1) |
Easy |
Math |
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189 |
Rotate Array |
Solution |
O(1) |
O(1) |
Easy |
Array |
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203 |
Remove Linked List Elements |
Solution |
O(n) |
O(1) |
Easy |
Linked List |
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204 |
Count Primes |
Solution |
O(n) |
O(n) |
Easy |
Hash Table, Math |
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206 |
Reverse Linked List |
Solution |
O(n) |
O(n) |
Easy |
Linked List |
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217 |
Contains Duplicate |
Solution |
O(n) |
O(n) |
Easy |
Array, Hash Table |
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219 |
Contains Duplicate II |
Solution |
O(n) |
O(n) |
Easy |
Array, Hash Table |
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231 |
Power of Two |
Solution |
O(1) |
O(1) |
Easy |
Math, Bit Manipulation |
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234 |
Palindrome Linked List |
Solution |
O(n) |
O(n) |
Easy |
Linked List, Two Pointers |
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237 |
Delete Node in a Linked List |
Solution |
O(1) |
O(1) |
Easy |
Linked List |
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242 |
Valid Anagram |
Solution |
O(n) |
O(n) |
Easy |
Hash Table, Sort |
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268 |
Missing Number |
Solution |
O(n) |
O(1) |
Easy |
Array, Math, Bit Manipulation |
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283 |
Move Zeroes |
Solution |
O(n) |
O(1) |
Easy |
Array, Two Pointers |
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287 |
Find the Duplicate Number |
Solution |
O(nlogn) |
O(1) |
Easy |
Array, Two Pointers, Binary Search |
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326 |
Power of Three |
Solution |
O(logn) |
O(1) |
Easy |
Math |
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328 |
Odd Even Linked List |
Solution |
O(n) |
O(1) |
Medium |
Linked List |
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344 |
Reverse String |
Solution |
O(1) |
O(1) |
Easy |
String, Two Pointer |
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345 |
Reverse Vowels of a String |
Solution |
O(n) |
O(1) |
Easy |
Two Pointers, String |
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367 |
Valid Perfect Square |
Solution |
O(n) |
O(1) |
Easy |
Math, Binary Search |
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389 |
Find the Difference |
Solution |
O(n) |
O(1) |
Easy |
Hash Table, Bit Manipulation |
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441 |
Arranging Coins |
Solution |
O(1) |
O(1) |
Easy |
Math, Binary Search |
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445 |
Add Two Numbers II |
Solution |
O(n) |
O(n) |
Medium |
Linked List |
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448 |
Find All Numbers Disappeared in an Array |
Solution |
O(n) |
O(n) |
Easy |
Array |
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461 |
Hamming Distance |
Solution |
O(n) |
O(1) |
Easy |
Bit Manipulation |
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476 |
Number Complement |
Solution |
O(n) |
O(n) |
Easy |
Bit Manipulation |
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485 |
Max Consecutive Ones |
Solution |
O(n) |
O(1) |
Easy |
Array |
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507 |
Perfect Number |
Solution |
O(logn) |
O(1) |
Easy |
Math |
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535 |
Encode and Decode TinyURL |
Solution |
O(1) |
O(1) |
Medium |
Hash Table, Math |
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557 |
Reverse Words in a String |
Solution |
O(n) |
O(1) |
Easy |
String |
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561 |
Array Partition I |
Solution |
O(n) |
O(1) |
Easy |
Array |
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566 |
Reshape the Matrix |
Solution |
O(n) |
O(n^2) |
Easy |
Array |
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599 |
Minimum Index Sum of Two Lists |
Solution |
O(n) |
O(n) |
Easy |
Hash Table |
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628 |
Maximum Product of Three Numbers |
Solution |
O(nlogn) |
O(1) |
Easy |
Array, Math |
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633 |
Sum of Square Numbers |
Solution |
O(logn) |
O(1) |
Easy |
Math |
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645 |
Set Mismatch |
Solution |
O(1) |
O(n) |
Easy |
Hash Table, Math |
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693 |
Binary Number with Alternating Bits |
Solution |
O(n) |
O(1) |
Easy |
Bit Manipulation |
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697 |
Degree of an Array |
Solution |
O(n) |
O(n) |
Easy |
Array |
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804 |
Unique Morse Code Words |
Solution |
O(n^2) |
O(n) |
Easy |
String |
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832 |
Flipping an Image |
Solution |
O(n^2) |
O(1) |
Easy |
Array |
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896 |
Monotonic Array |
Solution |
O(n) |
O(1) |
Easy |
Array |
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929 |
Unique Email Addresses |
Solution |
O(n) |
O(n) |
Easy |
String |
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