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

September LeetCoding Challenge 9

Description

The Number of Weak Characters in the Game

You are playing a game that contains multiple characters, and each of the characters has two main properties: attack and defense. You are given a 2D integer array properties where properties[i] = [attacki, defensei] represents the properties of the ith character in the game.

A character is said to be weak if any other character has both attack and defense levels strictly greater than this character's attack and defense levels. More formally, a character i is said to be weak if there exists another character j where attackj > attacki and defensej > defensei.

Return the number of weak characters.

Example 1:

Input: properties = [[5,5],[6,3],[3,6]]
Output: 0
Explanation: No character has strictly greater attack and defense than the other.

Example 2:

Input: properties = [[2,2],[3,3]]
Output: 1
Explanation: The first character is weak because the second character has a strictly greater attack and defense.

Example 3:

Input: properties = [[1,5],[10,4],[4,3]]
Output: 1
Explanation: The third character is weak because the second character has a strictly greater attack and defense.

Constraints:

• 2 <= properties.length <= 10^5
• properties[i].length == 2
• 1 <= attacki, defensei <= 10^5

Solution

auto speedup = [](){
  cin.tie(nullptr);
  cout.tie(nullptr);
  ios::sync_with_stdio(false);
  return 0;
}();
class Solution {
public:
  int numberOfWeakCharacters(vector<vector<int>>& properties) {
    sort(properties.begin(), properties.end(), [](const vector<int> &a, const vector<int> &b){
      return a[0] > b[0] || (a[0] == b[0] && a[1] > b[1]);
    });
    int mmax = 0;
    int cur = 0;
    int curMax = 0;
    int answer = 0;
    for(const auto &property : properties) {
      if(property[0] != cur) {
        cur = property[0];
        mmax = max(mmax, curMax);
        curMax = property[1];
      }
      if(property[1] < mmax) {
        answer += 1;
      }
    }
    return answer;
  }
};

// Accepted
// 44/44 cases passed (1242 ms)
// Your runtime beats 37.02 % of cpp submissions
// Your memory usage beats 99.91 % of cpp submissions (124.7 MB)