题解 | #最长无重复子数组#

双指针+哈希表

class Solution {
public:
    /**
     * 
     * @param arr int整型vector the array
     * @return int整型
     */
    int maxLength(vector<int>& arr) {
        // write code here
        
        unordered_map<int, int> tb;
        int left=0, right = 0;
        int res = 0;
        
        while(right < arr.size()){
            if(tb.find(arr[right]) == tb.end()){
                tb[arr[right]] += 1;
                right++;
                continue;
            }
            
            res = max(res, right-left);
            while(arr[left] != arr[right] && left < right){
                tb.erase(arr[left]);
                left++;
            }
            left++;
            right++;
        }
        
        res = max(res, right-left);
        
        return res;
    }
};