Practice Problems

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115 Problems
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Valid Palindrome
String Two Pointers
Easy
69.0%
+10 coins
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Missing Number
Array Bit Manipulation Math
Easy
71.2%
+10 coins
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Single Number
Array Bit Manipulation
Easy
66.4%
+10 coins
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Contains Duplicate
Array Hash Table
Easy
66.9%
+10 coins
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Best Time to Buy and Sell Stock
Array Dynamic Programming
Easy
69.1%
+10 coins
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Median of Two Sorted Arrays
Array Binary Search Divide and Conquer
Hard
91.7%
+50 coins
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K Closest Points to Origin
Array Heap (Priority Queue) Math Sorting
Medium
49.4%
+25 coins
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Binary Tree Level Order Traversal
Breadth-First Search Tree
Medium
47.8%
+25 coins
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Coin Change
Array Breadth-First Search Dynamic Programming
Medium
50.0%
+25 coins
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Number of Islands
Array Breadth-First Search Depth-First Search Matrix Union Find
Medium
47.9%
+25 coins
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Merge Intervals
Array Sorting
Medium
46.2%
+25 coins
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Longest Substring Without Repeating Characters
Hash Table Sliding Window String
Medium
36.6%
+25 coins
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Maximum Subarray
Array Divide and Conquer Dynamic Programming
Easy
69.3%
+10 coins
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Valid Parentheses
Stack String
Easy
65.9%
+10 coins
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Two Sum
Array Hash Table
Easy
69.7%
+10 coins
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