题解 | #最长无重复子数组#

1.统计不重复的长度
2.删除上次发生重复的数字之前的数

import java.util.HashMap;
import java.util.Map;

public class Solution {
    public int maxLength(int[] arr) {
        Map<Integer, Integer> m = new HashMap<>();
        int max = 0;
        int cur = 0;
        int j = 0;
        for (int i = 0; i < arr.length; i++) {
            int index = m.getOrDefault(arr[i], -1);
            if ( index == -1) {
                cur++;
                m.put(arr[i], i);
                if (cur > max) max = cur;
            } else {
                if (cur > max) max = cur;
                m.put(arr[i], i);
                for (; j < index; j++) {
                    if (m.getOrDefault(arr[j], -1) == j) {
                        m.remove(arr[j]);
                    }
                }
                cur = i - index;
            }
        }
        return max;
    }

    public static void main(String[] args) {
        int[] arr = {2,2,3,4,3};
//        int[] arr = {2,3,4,5};
        System.out.println(new Solution().maxLength(arr));
    }
}