add_binary/

Author: hitzzc

README.md

@@ -59,6 +59,7 @@ Golang solution for leetcode. For each problem, there is a simple *_test.go to t
 #### [64. minimum path sum](https://github.com/hitzzc/go-leetcode/tree/master/minimum_path_sum)
 #### [65. valid number](https://github.com/hitzzc/go-leetcode/tree/master/valid_number)
 #### [66. plus one](https://github.com/hitzzc/go-leetcode/tree/master/plus_one)
+#### [67. add binary](https://github.com/hitzzc/go-leetcode/tree/master/add_binary)
 
 
 

add_binary/add_binary.go

@@ -0,0 +1,39 @@
+package add_binary
+
+func addBinary(a string, b string) string {
+	aBytes, bBytes := []byte(a), []byte(b)
+	var carry, sum byte = '0', '0'
+	short, long := aBytes, bBytes
+	if len(aBytes) > len(bBytes) {
+		short, long = bBytes, aBytes
+	}
+	newShort := make([]byte, len(long)-len(short))
+	for i := range newShort {
+		newShort[i] = '0'
+	}
+	newShort = append(newShort, short...)
+	ret := make([]byte, len(long)+1)
+	for i := len(long) - 1; i >= 0; i-- {
+		sum, carry = add(newShort[i], long[i], carry)
+		ret[i+1] = sum
+	}
+	if carry == '1' {
+		ret[0] = carry
+	} else {
+		ret = ret[1:]
+	}
+	return string(ret)
+}
+
+func add(a, b, c byte) (byte, byte) {
+	if a == '0' && b == '0' {
+		return c, '0'
+	}
+	if a == '1' && b == '1' {
+		return c, '1'
+	}
+	if c == '1' {
+		return '0', '1'
+	}
+	return '1', '0'
+}

add_binary/add_binary_test.go

@@ -0,0 +1,9 @@
+package add_binary
+
+import (
+	"testing"
+)
+
+func TestAddBinary(t *testing.T) {
+	println(addBinary("010", "101"))
+}