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LeetCode-67-Add-Binary.java
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LeetCode-67-Add-Binary.java
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/*
LeetCode: https://leetcode.com/problems/add-binary/
LintCode: http://www.lintcode.com/problem/add-binary/
JiuZhang: http://www.jiuzhang.com/solutions/add-binary/
ProgramCreek: http://www.programcreek.com/2014/05/leetcode-add-binary-java/
Analysis:
*/
public class Solution {
// 1.
public String addBinary(String a, String b) {
if(a == null || a.length() == 0) return b;
if(b == null || b.length() == 0) return a;
int carry = 0;
int i = a.length() - 1;
int j = b.length() - 1;
String result = "";
while(i >= 0 || j >= 0){
int val = carry;
if(i >= 0){
int ai = Character.getNumericValue(a.charAt(i));
val += ai;
i--;
}
if(j >= 0){
int bi = Character.getNumericValue(b.charAt(j));
val += bi;
j--;
}
result = val % 2 + result;
carry = val / 2;
}
if(carry == 1) result = carry + result;
return result;
}
// 2.
public String addBinary(String a, String b) {
int carry = 0;
int i = a.length() - 1, j = b.length() - 1;
StringBuilder sb = new StringBuilder();
while (i >= 0 && j >= 0) {
int aNum = a.charAt(i) - '0';
int bNum = b.charAt(j) - '0';
int sum = aNum + bNum + carry;
sb.insert(0, sum % 2);
carry = sum / 2;
i--;
j--;
}
while (i >= 0) {
int aNum = a.charAt(i) - '0';
int sum = aNum + carry;
sb.insert(0, sum % 2);
carry = sum / 2;
i--;
}
while (j >= 0) {
int bNum = b.charAt(j) - '0';
int sum = bNum + carry;
sb.insert(0, sum % 2);
carry = sum / 2;
j--;
}
if (carry != 0) sb.insert(0, carry);
return sb.toString();
}
}