0190-Reverse-Bits

Problem Description

Reverse bits of a given 32 bits signed integer.

Solution

// Time: O(1)
// Space: O(1)
int reverseBits(int n) {
  int ans = 0;
  for (int i = 0; i < 32; ++i, n >>= 1) {
    ans = (ans << 1) | (n & 1);
  }
  return ans;
}