Today I have done leetcode's August LeetCoding Challenge with cpp.

August LeetCoding Challenge 26

Description

Maximum Length of Pair Chain

You are given an array of n pairs pairs where pairs[i] = [lefti, righti] and lefti < righti.

A pair p2 = [c, d] follows a pair p1 = [a, b] if b < c. A chain of pairs can be formed in this fashion.

Return the length longest chain which can be formed.

You do not need to use up all the given intervals. You can select pairs in any order.

Example 1:

Input: pairs = [[1,2],[2,3],[3,4]]
Output: 2
Explanation: The longest chain is [1,2] -> [3,4].

Example 2:

Input: pairs = [[1,2],[7,8],[4,5]]
Output: 3
Explanation: The longest chain is [1,2] -> [4,5] -> [7,8].

Constraints:

• n == pairs.length
• 1 <= n <= 1000
• -1000 <= lefti < righti <= 1000

Solution

class Solution {
public:
  int findLongestChain(vector<vector<int>>& pairs) {
    sort(pairs.begin(), pairs.end(), [](vector<int> &a, vector<int> &b) {
      return a[1] < b[1];
    });
    int cur = INT_MIN;
    int answer = 0;
    for(auto &p : pairs) {
      if(p[0] > cur) {
        cur = p[1];
        answer += 1;
      }
    }
    return answer;
  }
};

// Accepted
// 206/206 cases passed (43 ms)
// Your runtime beats 98.67 % of cpp submissions
// Your memory usage beats 86.44 % of cpp submissions (22.5 MB)