1695. Maximum Erasure Value

用sliding windows, 在用hash_table, 紀錄走過的index, 然後只要遇到重複的我們就滑動窗口,

class Solution {
public:
    int maximumUniqueSubarray(vector<int>& nums) {
        unordered_map<int, int> m;
        int left = 0;
        int res = 0;
        int sum = 0;
        for(int i = 0;i < nums.size();i++){
            sum += nums[i];
            if(m.count(nums[i]) && left <= m[nums[i]]){
                for(int j = left; j < m[nums[i]] + 1;j++){
                    sum -=nums[j];
                }
                left = m[nums[i]] + 1;
            }
            m[nums[i]] = i;
            res = max(sum, res);
        }
        return res;
        
    }
};