LC 452. Minimum Number of Arrows to Burst Balloons

https://leetcode.com/problems/minimum-number-of-arrows-to-burst-balloons/?envType=study-plan-v2&envId=top-interview-150

class Solution {
public:
    static const bool cmp (vector<int> &a, vector<int> &b) {
        return a[1] < b[1];
    }
    int findMinArrowShots(vector<vector<int>>& points) {
        int n = points.size();
        sort(points.begin(), points.end(), cmp);
        int ans = 0;
        int idx = 0;
        while (idx < n) {
            int last = points[idx][1];
            ans += 1;
            while (idx < n && points[idx][0] <= last && last <= points[idx][1]) idx += 1;
        }
        return ans;
    }
};

Time Complexity: O(nlogn)
Space: O(1)

感受一下 sort + gready 的題目，這題就是很明顯的 gready 了