Reverse String

easy

Reverse array of characters in-place using two pointers

Reverse String

Key Insight

Swap left and right elements, move both pointers inward until they meet

Step 1Initial Array
left
h
0
e
1
l
2
l
3
right
o
4
→converge←

Place pointers at both ends of the character array.

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Learn the Pattern

Two PointersUse two pointers to traverse an array or string, reducing time complexity from O(n^2) to O(n) for problems involving pairs or subarrays.
Practice the Code

Step-by-Step Walkthrough: Reverse String

Swap left and right elements, move both pointers inward until they meet

  1. Initial Array

    Place pointers at both ends of the character array.

  2. First Swap

    Swap "h" and "o".

  3. Move & Swap

    Move pointers, swap "e" and "l".

  4. Pointers Meet

    Pointers cross - we're done!

  5. Reversed!

    "hello" → "olleh"