1353_leetcode

1353. Maximum Number of Events That Can Be Attended

t = O(nlogn)
class Solution {
public:
    int maxEvents(vector<vector<int>>& events) {
        sort(events.begin(), events.end());  
        priority_queue<int, vector<int>, greater<int>> minHeap; 
        int i = 0, n = events.size();
        int day = 1, res = 0;

        while (i < n || !minHeap.empty()) {
            if (minHeap.empty()) {
                day = events[i][0];  
            }
            while (i < n && events[i][0] <= day) {
                minHeap.push(events[i][1]);  
                i++;
            }
            while (!minHeap.empty() && minHeap.top() < day) {
                minHeap.pop();  
            }
            if (!minHeap.empty()) {
                minHeap.pop(); 
                res++;
                day++;
            }
        }
        return res;
    }
};