leetcode

0 class Solution {

1 public:

2 int longestSubsequence(const vector<int> &arr, int diff) {

3 unordered_map<int, int> dp;

4

5 int res = 1;

6 for (int n : arr) {

7 int before = dp.count(n - diff) ? dp[n - diff] : 0;

8 res = max(res, dp[n] = before + 1);

9 }

10

11 return res;

12 }

13 };