package leetcode;
/**
* 给定两个å—符串形å¼çš„éžè´Ÿæ•´æ•° num1 å’Œnum2 ，计算它们的和。
*
*
* æ示：
*
* num1 å’Œnum2 的长度都å°äºŽ 5100
* num1 å’Œnum2 都åªåŒ…å«æ•°å— 0-9
* num1 å’Œnum2 都ä¸åŒ…å«ä»»ä½•å‰å¯¼é›¶
* ä½ ä¸èƒ½ä½¿ç”¨ä»»ä½•å…§å»º BigInteger 库， 也ä¸èƒ½ç›´æŽ¥å°†è¾“入的å—符串转æ¢ä¸ºæ•´æ•°å½¢å¼
*
* æ¥æºï¼šåŠ›æ‰£ï¼ˆLeetCode）
* 链接：https://leetcode-cn.com/problems/add-strings
* 著作æƒå½’领扣网络所有。商业转载请è”系官方授æƒï¼Œéžå•†ä¸šè½¬è½½è¯·æ³¨æ˜Žå‡ºå¤„。
*/
import java.util.Random;
class Solution {
private static boolean debug;
public static void main(String[] args) {
Solution solution = new Solution();
System.out.println(solution.addStrings("35829", "498989"));
//System.out.println(solution.addStrings("119019", "2193"));
debug=false;
if(debug){
Random random = new Random();
int count=random.nextInt(20)+5000000;
for (int i = 0; i < count; i++) {
int a = random.nextInt(200000);
int b = random.nextInt(500000);
String s = solution.addStrings(a + "", b + "");
if(!s.equals((a+b)+"")){
System.out.println("计算："+s+"\t实际"+(a+b));
System.out.println("num1:"+a);
System.out.println("num2:"+b);
return ;
}
}
}
}
public String addStrings(String num1, String num2) {
if(num1==null||num1.length()==0){
return num2;
}
if(num2==null||num2.length()==0){
return num1;
}
int len1=num1.length();
int len2=num2.length();
StringBuilder s=new StringBuilder();
//防æ¢å†™å¤šä¸ªif判æ–
if(len1