Add Binary

// 67. Add Binary // // https://leetcode.com/problems/add-binary/ // addBinary function adds the a, b given numbers by string. // The length of the a or b is quite big (onto the 10^4), so byte slice is required. // Digit and Carry are calculated by the bit manipulation because only 0 or 1 appeared. func addBinary(a string, b string) string { size := len(a) if size < len(b) { size = len(b) } number := make([]byte, size+1) var carry byte for i, j, k := len(a)-1, len(b)-1, size; i >= 0 || j >= 0; { var digitA, digitB, digit byte if i >= 0 { digitA = a[i] - '0' } if j >= 0 { digitB = b[j] - '0' } digit = digitA ^ digitB ^ carry carry = digitA&digitB | ((digitA | digitB) & carry) number[k] = digit + '0' i, j, k = i-1, j-1, k-1 } if carry == 1 { number[0] = '1' return string(number) } return string(number[1:]) }