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#13 Move Zeroes
Google Amazon Arrays Two Pointers
Easy
2000M
58.1%
Solve
#14 Valid Parentheses
Microsoft Strings Stack
Easy
3500M
40.3%
Solve
#15 Subarray Sum Equals K
Google Amazon Hash Table Prefix Sum
Medium
1700M
43.6%
Solve
#16 Permutations
Google Facebook Backtracking Arrays
Medium
2100M
72.5%
Solve
#17 Validate Binary Search Tree
Amazon Trees DFS
Medium
1850M
31.7%
Solve
#18 Merge K Sorted Lists
Google Heap Greedy
Hard
900M
45.2%
Solve
#19 Search in Rotated Sorted Array
Microsoft Binary Search
Medium
1600M
40.9%
Solve
#20 Merge Two Sorted Lists
Amazon Linked List
Easy
3000M
67.4%
Solve
#21 Number of Islands
Google Graphs BFS
Medium
2400M
53.1%
Solve
#22 Single Number
Apple Math Bit Manipulation
Easy
2700M
69.2%
Solve
#23 Word Search
Amazon Microsoft Matrix DFS
Medium
1950M
36.8%
Solve
#24 Trapping Rain Water
Google Dynamic Programming Greedy
Hard
1400M
61.0%
Solve