diff --git a/Algorithms/0732. My Calendar III/732. My Calendar III.go b/Algorithms/0732. My Calendar III/732. My Calendar III.go new file mode 100644 index 00000000..33620268 --- /dev/null +++ b/Algorithms/0732. My Calendar III/732. My Calendar III.go @@ -0,0 +1,71 @@ +package leetcode + +// SegmentTree732 define +type SegmentTree732 struct { + start, end, count int + left, right *SegmentTree732 +} + +// MyCalendarThree define +type MyCalendarThree struct { + st *SegmentTree732 + maxHeight int +} + +// Constructor732 define +func Constructor732() MyCalendarThree { + st := &SegmentTree732{ + start: 0, + end: 1e9, + } + return MyCalendarThree{ + st: st, + } +} + +// Book define +func (mct *MyCalendarThree) Book(start int, end int) int { + mct.st.book(start, end, &mct.maxHeight) + return mct.maxHeight +} + +func (st *SegmentTree732) book(start, end int, maxHeight *int) { + if start == end { + return + } + if start == st.start && st.end == end { + st.count++ + if st.count > *maxHeight { + *maxHeight = st.count + } + if st.left == nil { + return + } + } + if st.left == nil { + if start == st.start { + st.left = &SegmentTree732{start: start, end: end, count: st.count} + st.right = &SegmentTree732{start: end, end: st.end, count: st.count} + st.left.book(start, end, maxHeight) + return + } + st.left = &SegmentTree732{start: st.start, end: start, count: st.count} + st.right = &SegmentTree732{start: start, end: st.end, count: st.count} + st.right.book(start, end, maxHeight) + return + } + if start >= st.right.start { + st.right.book(start, end, maxHeight) + } else if end <= st.left.end { + st.left.book(start, end, maxHeight) + } else { + st.left.book(start, st.left.end, maxHeight) + st.right.book(st.right.start, end, maxHeight) + } +} + +/** + * Your MyCalendarThree object will be instantiated and called as such: + * obj := Constructor(); + * param_1 := obj.Book(start,end); + */ diff --git a/Algorithms/0732. My Calendar III/732. My Calendar III_test.go b/Algorithms/0732. My Calendar III/732. My Calendar III_test.go new file mode 100644 index 00000000..002acfaa --- /dev/null +++ b/Algorithms/0732. My Calendar III/732. My Calendar III_test.go @@ -0,0 +1,16 @@ +package leetcode + +import ( + "fmt" + "testing" +) + +func Test_Problem732(t *testing.T) { + obj := Constructor732() + fmt.Printf("book = %v\n\n", obj.Book(10, 20)) // returns 1 + fmt.Printf("book = %v\n\n", obj.Book(50, 60)) // returns 1 + fmt.Printf("book = %v\n\n", obj.Book(10, 40)) // returns 2 + fmt.Printf("book = %v\n\n", obj.Book(5, 15)) // returns 3 + fmt.Printf("book = %v\n\n", obj.Book(5, 10)) // returns 3 + fmt.Printf("book = %v\n\n", obj.Book(25, 55)) // returns 3 +} diff --git a/Algorithms/0732. My Calendar III/README.md b/Algorithms/0732. My Calendar III/README.md new file mode 100755 index 00000000..0f050dd1 --- /dev/null +++ b/Algorithms/0732. My Calendar III/README.md @@ -0,0 +1,63 @@ +# [732. My Calendar III](https://leetcode.com/problems/my-calendar-iii/) + + +## 题目: + +Implement a `MyCalendarThree` class to store your events. A new event can **always** be added. + +Your class will have one method, `book(int start, int end)`. Formally, this represents a booking on the half open interval `[start, end)`, the range of real numbers `x` such that `start <= x < end`. + +A K-booking happens when **K** events have some non-empty intersection (ie., there is some time that is common to all K events.) + +For each call to the method `MyCalendar.book`, return an integer `K` representing the largest integer such that there exists a `K`-booking in the calendar. + +Your class will be called like this: + +`MyCalendarThree cal = new MyCalendarThree();` + +`MyCalendarThree.book(start, end)` + +**Example 1:** + + MyCalendarThree(); + MyCalendarThree.book(10, 20); // returns 1 + MyCalendarThree.book(50, 60); // returns 1 + MyCalendarThree.book(10, 40); // returns 2 + MyCalendarThree.book(5, 15); // returns 3 + MyCalendarThree.book(5, 10); // returns 3 + MyCalendarThree.book(25, 55); // returns 3 + Explanation: + The first two events can be booked and are disjoint, so the maximum K-booking is a 1-booking. + The third event [10, 40) intersects the first event, and the maximum K-booking is a 2-booking. + The remaining events cause the maximum K-booking to be only a 3-booking. + Note that the last event locally causes a 2-booking, but the answer is still 3 because + eg. [10, 20), [10, 40), and [5, 15) are still triple booked. + +**Note:** + +- The number of calls to `MyCalendarThree.book` per test case will be at most `400`. +- In calls to `MyCalendarThree.book(start, end)`, `start` and `end` are integers in the range `[0, 10^9]`. + + +## 题目大意 + +实现一个 MyCalendar 类来存放你的日程安排,你可以一直添加新的日程安排。 + +MyCalendar 有一个 book(int start, int end)方法。它意味着在start到end时间内增加一个日程安排,注意,这里的时间是半开区间,即 [start, end), 实数 x 的范围为,  start <= x < end。当 K 个日程安排有一些时间上的交叉时(例如K个日程安排都在同一时间内),就会产生 K 次预订。每次调用 MyCalendar.book方法时,返回一个整数 K ,表示最大的 K 次预订。 + +请按照以下步骤调用MyCalendar 类: MyCalendar cal = new MyCalendar(); MyCalendar.book(start, end) + +说明: + +- 每个测试用例,调用 MyCalendar.book 函数最多不超过 400 次。 +- 调用函数 MyCalendar.book(start, end)时, start 和 end 的取值范围为 [0, 10^9]。 + + + + +## 解题思路 + +- 设计一个日程类,每添加一个日程,实时显示出当前排期中累计日程最多的个数,例如在一段时间内,排了 3 个日程,其他时间内都只有 0,1,2 个日程,则输出 3 。 +- 拿到这个题目以后会立即想到线段树。由于题目中只有增加日程,所以这一题难度不大。这一题和第 699 题也类似,但是有区别,第 699 题中,俄罗斯方块会依次摞起来,而这一题中,俄罗斯方块也就摞起来,但是方块下面如果是空挡,方块会断掉。举个例子:依次增加区间 [10,20],[10,40],[5,15],[5,10],如果是第 699 题的规则,这 [5,10] 的这块砖块会落在 [5,15] 上,从而使得高度为 4,但是这一题是日程,日程不一样,[5,15] 这个区间内有 3 个日程,但是其他部分都没有 3 个日程,所以第三块砖块 [5,15] 中的 [5,10] 会“断裂”,掉下去,第四块砖块还是 [5,10],落在第三块砖块断落下去的位置,它们俩落在一起的高度是 2 。 +- 构造一颗线段树,这里用树来构造,如果用数组需要开辟很大的空间。当区间左右边界和查询边界完全相同的时候再累加技术,否则不加,继续划分区间。以区间的左边界作为划分区间的标准,因为区间左边界是开区间,右边是闭区间。一个区间的计数值以区间左边界的计数为准。还是上面的例子,[5,10) 计数以 5 为标准,count = 2,[10,15) 计数以 10 为标准,count = 3 。还需要再动态维护一个最大值。这个线段树的实现比较简单。 +- 类似的题目有:第 715 题,第 218 题,第 699 题。第 715 题是区间更新定值(**不是增减**),第 218 题可以用扫描线,第 732 题和第 699 题类似,也是俄罗斯方块的题目,但是第 732 题的俄罗斯方块的方块会“断裂”。