對(duì)稱子字符串

Description

Given a string ‘str’ of digits, find length of the longest substring of ‘str’, such that the length of the substring is 2k digits and sum of left k digits is equal to the sum of right k digits.

給定一個(gè)數(shù)字字符串' str '，找出' str '的最長(zhǎng)子串的長(zhǎng)度，使該子串的長(zhǎng)度為2k，且左k位數(shù)字的和等于右k位數(shù)字的和。

Input

輸入第一行是測(cè)試用例的個(gè)數(shù)，后面每一行表示一個(gè)數(shù)字組成的字符串，例如："123123"

Output

輸出找到的滿足要求的最長(zhǎng)子串的長(zhǎng)度。例如，給定的例子長(zhǎng)度應(yīng)該是 6。每行對(duì)應(yīng)一個(gè)用例的結(jié)果。

Sample Input

1
1538023

Sample Output

4

Solution

public class SymmetricalSubstr {

    public static void main(String[] args){
        Scanner in = new Scanner(System.in);
        int caseNum = in.nextInt();
        for(int i = 0; i < caseNum; i++){
            in.nextLine();
            String str = in.next();
            System.out.println(getLongestLen(str));
        }
    }

    public static int getLongestLen(String str){
        int max = 0;
        int strLen = str.length();
        for(int i = 0; i < strLen - 1; i++){
            int left = i;
            int right = i + 1;
            int leftSum = 0;
            int rightSum = 0;
            while(left >= 0 && right < strLen){
                leftSum += str.charAt(left) - '0';
                rightSum += str.charAt(right) - '0';
                if(leftSum == rightSum){
                    max = Math.max(max, right - left + 1);
                }
                left--;
                right++;
            }
        }
        return max;
    }
}