// 190. Reverse Bits #include "leetcode.h" #include /* * reverse the bitof a given 32 bits unsigned integer. */ uint32_t reverseBits(uint32_t n) { n = ((n & 0xFFFF0000) >> 16) | ((n & 0x0000FFFF) << 16); n = ((n & 0xFF00FF00) >> 8) | ((n & 0x00FF00FF) << 8); n = ((n & 0xF0F0F0F0) >> 4) | ((n & 0x0F0F0F0F) << 4); n = ((n & 0xCCCCCCCC) >> 2) | ((n & 0x33333333) << 2); n = ((n & 0xAAAAAAAA) >> 1) | ((n & 0x55555555) << 1); return n; } int main() { uint32_t n1 = 0b00000010100101000001111010011100; uint32_t n2 = 0b11111111111111111111111111111101; uint32_t r1 = reverseBits(n1); uint32_t r2 = reverseBits(n2); printf("%d (", r1); // expect: 964176192 (00111001011110000010100101000000) while (r1) { printf("%d", r1 & 1 ? 1 : 0); r1 >>= 1; } printf(")\n"); printf("%d (", r2); // expect: 3221225471 (10111111111111111111111111111111) while (r2) { printf("%d", r2 & 1 ? 1 : 0); r2 >>= 1; } printf(")\n"); }