题解 | #最长公共子串#

和求数组中子数组和最大值题目思路一样，从前往后依次排：
public class Solution {
/**
* longest common substring
* @param str1 string字符串 the string
* @param str2 string字符串 the string
* @return string字符串
*/
public String LCS (String str1, String str2) {
String result = "";
int start = 0;
int end = 1;
for(int i = 1;i <= str1.length();i++){
end = i;
if(str2.indexOf(str1.substring(start,end)) != -1){
if(str1.substring(start,end).length() > result.length()){
result = str1.substring(start,end);
}
}else{
start = i-2;
}
}
return result;
}
}