比较版本号
此题可采用双指针的的解法。
public int compare (String version1, String version2) {
// write code here
int n1=version1.length(),n2=version2.length(),len1=0,len2=0;
while (len1<n1&&len2<n2){
int num1=0,num2=0;
while (len1<n1&&version1.charAt(len1)!='.'){
num1=num1*10+(version1.charAt(len1++)-'0');
}
while (len2<n2&&version2.charAt(len2)!='.'){
num2=num2*10+(version2.charAt(len2++)-'0');
}
if (num1>num2){
return 1;
}else if(num2>num1){
return -1;
}
len1++;
len2++;
}
return 0;
}