package Strings;

import org.junit.Test;

/**

* @description: 描述 Easy

* @author: dekai.kong

* @date: 2018-12-13 17:22

* @from https://leetcode.com/problems/add-binary/

* Given two binary strings, return their sum (also a binary string).

*

* The input strings are both non-empty and contains only characters 1 or 0.

*

* Example 1:

*

* Input: a = "11", b = "1"

* Output: "100"

* Example 2:

*

* Input: a = "1010", b = "1011"

* Output: "10101"

*/

public class AddBinary {

public AddBinary() {

}

/**

* Runtime: 2 ms, faster than 97.12% of Java online submissions for Add Binary.

* 遍历到底

* @param a

* @param b

* @return

*/

public String addBinary(String a, String b) {

char[] ax = a.toCharArray();

char[] bx = b.toCharArray();

int up = 0;

int la = ax.length-1;

int lb = bx.length-1;

StringBuilder sb = new StringBuilder();

while(la>=0||lb>=0){

int avl = 0;

int bvl = 0;

if(la>=0){

avl = ax[la]=='0' ?0:1;

}

if(lb>=0){

bvl = bx[lb]=='0' ?0:1;;

}

if ((avl & bvl) == 1 ){

sb.insert(0,up);

up = 1;

}else if(((avl ^ bvl) & up) == 1){

sb.insert(0,0);

up = 1;

}else{

sb.insert(0,(avl ^ bvl)+up);

up = 0;

}

la--;

lb--;

}

if (up == 1) {sb.insert(0,1);}

return sb.toString();

}

@Test

public void test() {

System.out.println(addBinary("1010","1011"));

System.out.println(addBinary("1111","1111"));

System.out.println(addBinary("11","1"));

}

}