[Google] LeetCode 729 My Calendar I

You are implementing a program to use as your calendar. We can add a new event if adding the event will not cause a double booking.

A double booking happens when two events have some non-empty intersection (i.e., some moment is common to both events.).

The event can be represented as a pair of integers start and end that represents a booking on the half-open interval [start, end), the range of real numbers x such that start <= x < end.

Implement the MyCalendar class:

• MyCalendar() Initializes the calendar object.
• boolean book(int start, int end) Returns true if the event can be added to the calendar successfully without causing a double booking. Otherwise, return false and do not add the event to the calendar.

Solution

我们用 \(vector\) 套 \(pair\) 来维护时间坐标。那么如何查找当前的时间间隔是否与之前的有重叠呢

一种办法就是朴素的暴力 \(O(N)\), 不妨二分位置，如果在二分的过程中出现了重叠，那么直接 \(false\) 即可；否则在二分出的位置中插入当前的区间

class MyCalendar {
private:
    vector<pair<int,int>> t;
public:
    MyCalendar() {
        
    }
    
    bool book(int start, int end) {
        int n = t.size();
        int l = 0, r = n-1;
        int mid;
        while(l<=r){
            mid = l+(r-l)/2;
            int curs = t[mid].first, cure = t[mid].second;
            if(max(start, curs)<=min(end-1,cure))return false;
            else if(start<curs) r=mid-1;
            else l=mid+1;
        }
        t.insert(t.begin()+l, {start, end-1});
        return true;
    }
};

/**
 * Your MyCalendar object will be instantiated and called as such:
 * MyCalendar* obj = new MyCalendar();
 * bool param_1 = obj->book(start,end);
 */