题解 | #公共子串计算#

// 注意类名必须为 Main, 不要有任何 package xxx 信息
public class Main {
    public static void main(String[] args) {
        Scanner in = new Scanner(System.in);
        // 注意 hasNext 和 hasNextLine 的区别
        String str1 = in.next();
        String str2 = in.next();
        int length1 = str1.length();
        int length2 = str2.length();
        int max = 0;
        for(int i = 0; i < length1; i++){
            for(int j = 0; j < length2; j++){
                if(str1.charAt(i) == str2.charAt(j)){
                    max = Math.max(max, checkLongest(str1, str2, i, j));
                }
            }
        }
        System.out.println(max);
    }
    
    public static int checkLongest(String str1, String str2, int i, int j){
        if(i >= str1.length() || j >= str2.length() || str1.charAt(i) != str2.charAt(j)){
            return 0;
        }
        return 1 + checkLongest(str1, str2, i+1, j+1);
        
    }
}