33. Detect Circular Pattern Match

#include <stdio.h>
#include <stdint.h>

uint16_t rotate_right(uint16_t reg) {
    if (reg & 1)
        return ((reg >> 1) | 0x8000);
    else
        return (reg >> 1);
}

uint8_t is_circular_match(uint16_t reg, uint16_t target) {
    // Your code here
    uint16_t i, match=0;
    for (i=0; (i < 16) && (!match); i++) {
        reg= rotate_right(reg);
        if ((reg ^ target) == 0)
            match = 1;
    }
    return match;
}

int main() {
    uint16_t reg, target;
    scanf("%hu %hu", &reg, &target);
    printf("%hhu", is_circular_match(reg, target));
    return 0;
}

two registers will match if the bitwise exclusive XOR gives 0;

so rotate the register and compare