Find all Duplicate Numbers (easy)

Problem Statement

We are given an unsorted array containing n numbers taken from the range 1 to n. The array has some numbers appearing twice, find all these duplicate numbers using constant space.

Example 1:

Input: [3, 4, 4, 5, 5]
Output: [4, 5]

Example 2:

Input: [5, 4, 7, 2, 3, 5, 3]
Output: [3, 5]

Try it yourself

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Introduction

Pattern: Sliding Window

Pattern: Two Pointers

Pattern: Fast and Slow Patterns

Pattern: Merge Intervals

Pattern: Cyclic Sort

Pattern: In-place Reversal of a LinkedList

Pattern: Tree Breadth First Search

Pattern: Tree Depth First Search

Pattern: Two Heaps

Pattern: Subsets

Pattern: Modified Binary Search

Pattern: Bitwise XOR

Pattern: Top 'K' Elements

Pattern: K-way merge

Pattern : 0/1 Knapsack (Dynamic Programming)

Pattern: Topological Sort (Graph)

Miscellaneous

Conclusions

Find all Duplicate Numbers (easy)

Problem Statement

Try it yourself