这两段代码有什么不同吗?执行结果都一样

Question

第一段

public String getMaxSameString(String str1, String str2){
        String maxStr = (str1.length() >= str2.length()) ? str1 : str2;
        String minStr = (str1.length() < str2.length()) ? str1 : str2;
        int length = minStr.length();

        for (int i = 0; i < length; i++){
            for (int x = 0, y = length - i;y <= length;x++, y++){
                System.out.println(y);
                String substring = minStr.substring(x, y);
                if (maxStr.contains(substring)){
                    return substring;
                }
            }
        }
        return null;
    }

第二段

public String a(String str1, String str2){
        String maxStr = str1.length() >= str2.length() ? str1 : str2;
        String minStr = str1.length() < str2.length() ? str1 : str2;
        int length = minStr.length();
        for (int i = 0; i < length; i++){
            String subStr = minStr.substring(i);
            if (maxStr.contains(subStr)){
                return subStr;
            }
        }
        return null;
    }

Answer 1

时间复杂都不一样，如果结果一样后面的更高效。