165.比较版本号

方法：使用双指针

class Solution {public int compareVersion(String version1, String version2) {//使用双指针int n = version1.length(),m = version2.length();int i = 0,j = 0;while(i<n || j <m){int x = 0;for(; i < n && version1.charAt(i)!='.';i++){x = x * 10 + version1.charAt(i) - '0';}++i;  //跳过点号int y = 0;for( ; j < m &&  version2.charAt(j) !='.'; j++){y = y * 10 + version2.charAt(j) - '0';}++j;if(x!=y){return x > y ? 1:-1;}}return 0;}
}