题解 | #最长无重复子数组#

/**

• @Author: Mr.huang

• @Date: 2021/08/10/9:32

• @Description: NC41 最长无重复子数组 利用双指针做窗口，利用哈希去重

• /
  public class NC41 {
  public static void main(String[] args) {

    int [] array={1,1,2,2,5};
    int maxLength = getMaxLength(array);
    System.out.println(maxLength);

  }

  public static int getMaxLength(int[] arr){

    int maxLength=0;
    int left=0;
    int right=0;
    Map<Integer,Integer> map=new HashMap<>();
    if (arr==null||arr.length==0){
        return maxLength;
    }
    while (right<arr.length){
        map.put(arr[right], map.getOrDefault(arr[right],0)+1);
        int numInMap= arr[right];
        right++;
        while (map.get(numInMap)>1){
            int numOutMap=arr[left];
            left++;
            map.put(numOutMap,map.getOrDefault(numOutMap,0)-1);
        }
  
        maxLength=Math.max(maxLength,right-left);
    }
    return maxLength;

  }