/reverse-integer-c

C solution to a LeetCode #7 (Reverse Integer) problem, fully documented and analyzed with an emphasis on optimal runtime and memory efficiency.

Primary LanguageC

Reverse Integer 🌀

Problem Description

The task is to reverse the digits of a 32-bit signed integer.

  • Input: an integer x.
  • Output: the reversed digits of x.
  • Constraint: if the reversed value goes outside the 32-bit signed integer range
    [-2,147,483,648, 2,147,483,647], return 0 instead.

Examples:

  • 123 → 321
  • -123 → -321
  • 120 → 21
  • 1534236469 → 0 (overflow)

You can read the full problem statement here:
🔗 LeetCode – Reverse Integer

My Solution Complexity 🚀

  • Time Complexity: O(n)
    ✅ Beat 100% of C submissions on LeetCode.

  • Space Complexity: O(n)
    📦 Beat 71.5% of C submissions.

Screenshots 📸

Case Screenshot
Time Complexity Performance Screenshot
Space Complexity Performance Screenshot
Accepted Submission Accepted Screenshot

Self Feedback 💡

Solving this problem was a journey of debugging and optimization.
At first, I struggled with overflow cases (1534236469, -2147483648) and the precision issues of pow().
By switching to an integer-only power function, adding early overflow checks, and handling negatives carefully, I finally built a robust solution.

Seeing the result — 100% time and 71.5% space — felt rewarding.
It showed me how important it is to consider edge cases and to think about both performance and correctness.
Next step: I’ll explore how to reduce space complexity closer to O(1) while keeping the same speed.