diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README.md b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README.md index 14ff47eb20577..d10fa65816bfc 100644 --- a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README.md +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README.md @@ -106,7 +106,45 @@ tags: -### 方法一 +### 方法一：贪心 + +根据题目描述，对于会议 $i$，我们记它左侧非空闲位置为 $l_i$，右侧非空闲位置为 $r_i$，记会议 $i$ 的时长为 $w_i = \text{endTime}[i] - \text{startTime}[i]$，则： + +$$ +l_i = \begin{cases} +0 & i = 0 \\\\ +\text{endTime}[i - 1] & i \gt 0 +\end{cases} +$$ + +$$ +r_i = \begin{cases} +\text{eventTime} & i = n - 1 \\\\ +\text{startTime}[i + 1] & i \lt n - 1 +\end{cases} +$$ + +那么它可以向左移动，也可以向右移动，此时空闲时间为： + +$$ +r_i - l_i - w_i +$$ + +如果左侧存在最大的空闲时间 $\text{pre}_{i - 1}$，满足 $\text{pre}_{i - 1} \geq w_i$，则可以将会议 $i$ 向左移动到该位置，得到新的空闲时间： + +$$ +r_i - l_i +$$ + +同理，如果右侧存在最大的空闲时间 $\text{suf}_{i + 1}$，满足 $\text{suf}_{i + 1} \geq w_i$，则可以将会议 $i$ 向右移动到该位置，得到新的空闲时间： + +$$ +r_i - l_i +$$ + +因此，我们首先预处理两个数组 $\text{pre}$ 和 $\text{suf}$，其中 $\text{pre}[i]$ 表示 $[0, i]$ 范围内的最大空闲时间，$\text{suf}[i]$ 表示 $[i, n - 1]$ 范围内的最大空闲时间。然后遍历每个会议 $i$，计算它移动后的最大空闲时间，取最大值即可。 + +时间复杂度 $O(n)$，空间复杂度 $O(n)$。其中 $n$ 为会议的数量。 @@ -118,63 +156,223 @@ class Solution: self, eventTime: int, startTime: List[int], endTime: List[int] ) -> int: n = len(startTime) - res = 0 - - left_gaps = [0] * n - left_gaps[0] = startTime[0] - for meet in range(1, n): - left_gaps[meet] = max( - left_gaps[meet - 1], startTime[meet] - endTime[meet - 1] - ) - - right_gaps = [0] * n - right_gaps[n - 1] = eventTime - endTime[-1] - for meet in range(n - 2, -1, -1): - right_gaps[meet] = max( - right_gaps[meet + 1], startTime[meet + 1] - endTime[meet] - ) - - for meet in range(n): - left_gap = ( - left_gaps[meet] if meet == 0 else startTime[meet] - endTime[meet - 1] - ) - right_gap = ( - right_gaps[meet] - if meet == n - 1 - else startTime[meet + 1] - endTime[meet] - ) - - interval = 0 - - if ( - meet != 0 - and left_gaps[meet - 1] >= (endTime[meet] - startTime[meet]) - or meet != n - 1 - and right_gaps[meet + 1] >= (endTime[meet] - startTime[meet]) - ): - interval = endTime[meet] - startTime[meet] - - res = max(res, left_gap + interval + right_gap) - - return res + pre = [0] * n + suf = [0] * n + pre[0] = startTime[0] + suf[n - 1] = eventTime - endTime[-1] + for i in range(1, n): + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]) + for i in range(n - 2, -1, -1): + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]) + ans = 0 + for i in range(n): + l = 0 if i == 0 else endTime[i - 1] + r = eventTime if i == n - 1 else startTime[i + 1] + w = endTime[i] - startTime[i] + ans = max(ans, r - l - w) + if i and pre[i - 1] >= w: + ans = max(ans, r - l) + elif i + 1 < n and suf[i + 1] >= w: + ans = max(ans, r - l) + return ans ``` #### Java ```java - +class Solution { + public int maxFreeTime(int eventTime, int[] startTime, int[] endTime) { + int n = startTime.length; + int[] pre = new int[n]; + int[] suf = new int[n]; + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; i++) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; + } +} ``` #### C++ ```cpp - +class Solution { +public: + int maxFreeTime(int eventTime, vector& startTime, vector& endTime) { + int n = startTime.size(); + vector pre(n), suf(n); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; ++i) { + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; --i) { + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; ++i) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = max(ans, r - l); + } + } + + return ans; + } +}; ``` #### Go ```go +func maxFreeTime(eventTime int, startTime []int, endTime []int) int { + n := len(startTime) + pre := make([]int, n) + suf := make([]int, n) + + pre[0] = startTime[0] + suf[n-1] = eventTime - endTime[n-1] + + for i := 1; i < n; i++ { + pre[i] = max(pre[i-1], startTime[i]-endTime[i-1]) + } + + for i := n - 2; i >= 0; i-- { + suf[i] = max(suf[i+1], startTime[i+1]-endTime[i]) + } + + ans := 0 + for i := 0; i < n; i++ { + l := 0 + if i > 0 { + l = endTime[i-1] + } + r := eventTime + if i < n-1 { + r = startTime[i+1] + } + w := endTime[i] - startTime[i] + ans = max(ans, r-l-w) + + if i > 0 && pre[i-1] >= w { + ans = max(ans, r-l) + } else if i+1 < n && suf[i+1] >= w { + ans = max(ans, r-l) + } + } + + return ans +} +``` + +#### TypeScript + +```ts +function maxFreeTime(eventTime: number, startTime: number[], endTime: number[]): number { + const n = startTime.length; + const pre: number[] = Array(n).fill(0); + const suf: number[] = Array(n).fill(0); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (let i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (let i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + let ans = 0; + for (let i = 0; i < n; i++) { + const l = i === 0 ? 0 : endTime[i - 1]; + const r = i === n - 1 ? eventTime : startTime[i + 1]; + const w = endTime[i] - startTime[i]; + + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; +} +``` +#### Rust + +```rust +impl Solution { + pub fn max_free_time(event_time: i32, start_time: Vec, end_time: Vec) -> i32 { + let n = start_time.len(); + let mut pre = vec![0; n]; + let mut suf = vec![0; n]; + + pre[0] = start_time[0]; + suf[n - 1] = event_time - end_time[n - 1]; + + for i in 1..n { + pre[i] = pre[i - 1].max(start_time[i] - end_time[i - 1]); + } + + for i in (0..n - 1).rev() { + suf[i] = suf[i + 1].max(start_time[i + 1] - end_time[i]); + } + + let mut ans = 0; + for i in 0..n { + let l = if i == 0 { 0 } else { end_time[i - 1] }; + let r = if i == n - 1 { event_time } else { start_time[i + 1] }; + let w = end_time[i] - start_time[i]; + ans = ans.max(r - l - w); + + if i > 0 && pre[i - 1] >= w { + ans = ans.max(r - l); + } else if i + 1 < n && suf[i + 1] >= w { + ans = ans.max(r - l); + } + } + + ans + } +} ``` diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README_EN.md b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README_EN.md index dd6380c9fb3c3..299a32dd89889 100644 --- a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README_EN.md +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/README_EN.md @@ -104,7 +104,45 @@ tags: -### Solution 1 +### Solution 1: Greedy + +According to the problem description, for meeting $i$, let $l_i$ be the non-free position to its left, $r_i$ be the non-free position to its right, and let the duration of meeting $i$ be $w_i = \text{endTime}[i] - \text{startTime}[i]$. Then: + +$$ +l_i = \begin{cases} +0 & i = 0 \\\\ +\text{endTime}[i - 1] & i > 0 +\end{cases} +$$ + +$$ +r_i = \begin{cases} +\text{eventTime} & i = n - 1 \\\\ +\text{startTime}[i + 1] & i < n - 1 +\end{cases} +$$ + +The meeting can be moved to the left or right, and the free time in this case is: + +$$ +r_i - l_i - w_i +$$ + +If there exists a maximum free time on the left, $\text{pre}_{i - 1}$, such that $\text{pre}_{i - 1} \geq w_i$, then meeting $i$ can be moved to that position on the left, resulting in a new free time: + +$$ +r_i - l_i +$$ + +Similarly, if there exists a maximum free time on the right, $\text{suf}_{i + 1}$, such that $\text{suf}_{i + 1} \geq w_i$, then meeting $i$ can be moved to that position on the right, resulting in a new free time: + +$$ +r_i - l_i +$$ + +Therefore, we first preprocess two arrays, $\text{pre}$ and $\text{suf}$, where $\text{pre}[i]$ represents the maximum free time in the range $[0, i]$, and $\text{suf}[i]$ represents the maximum free time in the range $[i, n - 1]$. Then, for each meeting $i$, we calculate the maximum free time after moving it, and take the maximum value. + +The time complexity is $O(n)$, and the space complexity is $O(n)$, where $n$ is the number of meetings. @@ -116,63 +154,223 @@ class Solution: self, eventTime: int, startTime: List[int], endTime: List[int] ) -> int: n = len(startTime) - res = 0 - - left_gaps = [0] * n - left_gaps[0] = startTime[0] - for meet in range(1, n): - left_gaps[meet] = max( - left_gaps[meet - 1], startTime[meet] - endTime[meet - 1] - ) - - right_gaps = [0] * n - right_gaps[n - 1] = eventTime - endTime[-1] - for meet in range(n - 2, -1, -1): - right_gaps[meet] = max( - right_gaps[meet + 1], startTime[meet + 1] - endTime[meet] - ) - - for meet in range(n): - left_gap = ( - left_gaps[meet] if meet == 0 else startTime[meet] - endTime[meet - 1] - ) - right_gap = ( - right_gaps[meet] - if meet == n - 1 - else startTime[meet + 1] - endTime[meet] - ) - - interval = 0 - - if ( - meet != 0 - and left_gaps[meet - 1] >= (endTime[meet] - startTime[meet]) - or meet != n - 1 - and right_gaps[meet + 1] >= (endTime[meet] - startTime[meet]) - ): - interval = endTime[meet] - startTime[meet] - - res = max(res, left_gap + interval + right_gap) - - return res + pre = [0] * n + suf = [0] * n + pre[0] = startTime[0] + suf[n - 1] = eventTime - endTime[-1] + for i in range(1, n): + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]) + for i in range(n - 2, -1, -1): + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]) + ans = 0 + for i in range(n): + l = 0 if i == 0 else endTime[i - 1] + r = eventTime if i == n - 1 else startTime[i + 1] + w = endTime[i] - startTime[i] + ans = max(ans, r - l - w) + if i and pre[i - 1] >= w: + ans = max(ans, r - l) + elif i + 1 < n and suf[i + 1] >= w: + ans = max(ans, r - l) + return ans ``` #### Java ```java - +class Solution { + public int maxFreeTime(int eventTime, int[] startTime, int[] endTime) { + int n = startTime.length; + int[] pre = new int[n]; + int[] suf = new int[n]; + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; i++) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; + } +} ``` #### C++ ```cpp - +class Solution { +public: + int maxFreeTime(int eventTime, vector& startTime, vector& endTime) { + int n = startTime.size(); + vector pre(n), suf(n); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; ++i) { + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; --i) { + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; ++i) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = max(ans, r - l); + } + } + + return ans; + } +}; ``` #### Go ```go +func maxFreeTime(eventTime int, startTime []int, endTime []int) int { + n := len(startTime) + pre := make([]int, n) + suf := make([]int, n) + + pre[0] = startTime[0] + suf[n-1] = eventTime - endTime[n-1] + + for i := 1; i < n; i++ { + pre[i] = max(pre[i-1], startTime[i]-endTime[i-1]) + } + + for i := n - 2; i >= 0; i-- { + suf[i] = max(suf[i+1], startTime[i+1]-endTime[i]) + } + + ans := 0 + for i := 0; i < n; i++ { + l := 0 + if i > 0 { + l = endTime[i-1] + } + r := eventTime + if i < n-1 { + r = startTime[i+1] + } + w := endTime[i] - startTime[i] + ans = max(ans, r-l-w) + + if i > 0 && pre[i-1] >= w { + ans = max(ans, r-l) + } else if i+1 < n && suf[i+1] >= w { + ans = max(ans, r-l) + } + } + + return ans +} +``` + +#### TypeScript + +```ts +function maxFreeTime(eventTime: number, startTime: number[], endTime: number[]): number { + const n = startTime.length; + const pre: number[] = Array(n).fill(0); + const suf: number[] = Array(n).fill(0); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (let i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (let i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + let ans = 0; + for (let i = 0; i < n; i++) { + const l = i === 0 ? 0 : endTime[i - 1]; + const r = i === n - 1 ? eventTime : startTime[i + 1]; + const w = endTime[i] - startTime[i]; + + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; +} +``` +#### Rust + +```rust +impl Solution { + pub fn max_free_time(event_time: i32, start_time: Vec, end_time: Vec) -> i32 { + let n = start_time.len(); + let mut pre = vec![0; n]; + let mut suf = vec![0; n]; + + pre[0] = start_time[0]; + suf[n - 1] = event_time - end_time[n - 1]; + + for i in 1..n { + pre[i] = pre[i - 1].max(start_time[i] - end_time[i - 1]); + } + + for i in (0..n - 1).rev() { + suf[i] = suf[i + 1].max(start_time[i + 1] - end_time[i]); + } + + let mut ans = 0; + for i in 0..n { + let l = if i == 0 { 0 } else { end_time[i - 1] }; + let r = if i == n - 1 { event_time } else { start_time[i + 1] }; + let w = end_time[i] - start_time[i]; + ans = ans.max(r - l - w); + + if i > 0 && pre[i - 1] >= w { + ans = ans.max(r - l); + } else if i + 1 < n && suf[i + 1] >= w { + ans = ans.max(r - l); + } + } + + ans + } +} ``` diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.cpp b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.cpp new file mode 100644 index 0000000000000..1a2abf6658ece --- /dev/null +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.cpp @@ -0,0 +1,34 @@ +class Solution { +public: + int maxFreeTime(int eventTime, vector& startTime, vector& endTime) { + int n = startTime.size(); + vector pre(n), suf(n); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; ++i) { + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; --i) { + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; ++i) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = max(ans, r - l); + } + } + + return ans; + } +}; diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.go b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.go new file mode 100644 index 0000000000000..3738b7c9c2435 --- /dev/null +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.go @@ -0,0 +1,38 @@ +func maxFreeTime(eventTime int, startTime []int, endTime []int) int { + n := len(startTime) + pre := make([]int, n) + suf := make([]int, n) + + pre[0] = startTime[0] + suf[n-1] = eventTime - endTime[n-1] + + for i := 1; i < n; i++ { + pre[i] = max(pre[i-1], startTime[i]-endTime[i-1]) + } + + for i := n - 2; i >= 0; i-- { + suf[i] = max(suf[i+1], startTime[i+1]-endTime[i]) + } + + ans := 0 + for i := 0; i < n; i++ { + l := 0 + if i > 0 { + l = endTime[i-1] + } + r := eventTime + if i < n-1 { + r = startTime[i+1] + } + w := endTime[i] - startTime[i] + ans = max(ans, r-l-w) + + if i > 0 && pre[i-1] >= w { + ans = max(ans, r-l) + } else if i+1 < n && suf[i+1] >= w { + ans = max(ans, r-l) + } + } + + return ans +} diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.java b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.java new file mode 100644 index 0000000000000..a16bee2103c45 --- /dev/null +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.java @@ -0,0 +1,34 @@ +class Solution { + public int maxFreeTime(int eventTime, int[] startTime, int[] endTime) { + int n = startTime.length; + int[] pre = new int[n]; + int[] suf = new int[n]; + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (int i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (int i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + int ans = 0; + for (int i = 0; i < n; i++) { + int l = (i == 0) ? 0 : endTime[i - 1]; + int r = (i == n - 1) ? eventTime : startTime[i + 1]; + int w = endTime[i] - startTime[i]; + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; + } +} diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.py b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.py index 326b1b6aacc0a..fa4077f393055 100644 --- a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.py +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.py @@ -1,44 +1,24 @@ -class Solution: - def maxFreeTime( - self, eventTime: int, startTime: List[int], endTime: List[int] - ) -> int: - n = len(startTime) - res = 0 - - left_gaps = [0] * n - left_gaps[0] = startTime[0] - for meet in range(1, n): - left_gaps[meet] = max( - left_gaps[meet - 1], startTime[meet] - endTime[meet - 1] - ) - - right_gaps = [0] * n - right_gaps[n - 1] = eventTime - endTime[-1] - for meet in range(n - 2, -1, -1): - right_gaps[meet] = max( - right_gaps[meet + 1], startTime[meet + 1] - endTime[meet] - ) - - for meet in range(n): - left_gap = ( - left_gaps[meet] if meet == 0 else startTime[meet] - endTime[meet - 1] - ) - right_gap = ( - right_gaps[meet] - if meet == n - 1 - else startTime[meet + 1] - endTime[meet] - ) - - interval = 0 - - if ( - meet != 0 - and left_gaps[meet - 1] >= (endTime[meet] - startTime[meet]) - or meet != n - 1 - and right_gaps[meet + 1] >= (endTime[meet] - startTime[meet]) - ): - interval = endTime[meet] - startTime[meet] - - res = max(res, left_gap + interval + right_gap) - - return res \ No newline at end of file +class Solution: + def maxFreeTime( + self, eventTime: int, startTime: List[int], endTime: List[int] + ) -> int: + n = len(startTime) + pre = [0] * n + suf = [0] * n + pre[0] = startTime[0] + suf[n - 1] = eventTime - endTime[-1] + for i in range(1, n): + pre[i] = max(pre[i - 1], startTime[i] - endTime[i - 1]) + for i in range(n - 2, -1, -1): + suf[i] = max(suf[i + 1], startTime[i + 1] - endTime[i]) + ans = 0 + for i in range(n): + l = 0 if i == 0 else endTime[i - 1] + r = eventTime if i == n - 1 else startTime[i + 1] + w = endTime[i] - startTime[i] + ans = max(ans, r - l - w) + if i and pre[i - 1] >= w: + ans = max(ans, r - l) + elif i + 1 < n and suf[i + 1] >= w: + ans = max(ans, r - l) + return ans diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.rs b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.rs new file mode 100644 index 0000000000000..4373954f3e622 --- /dev/null +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.rs @@ -0,0 +1,38 @@ +impl Solution { + pub fn max_free_time(event_time: i32, start_time: Vec, end_time: Vec) -> i32 { + let n = start_time.len(); + let mut pre = vec![0; n]; + let mut suf = vec![0; n]; + + pre[0] = start_time[0]; + suf[n - 1] = event_time - end_time[n - 1]; + + for i in 1..n { + pre[i] = pre[i - 1].max(start_time[i] - end_time[i - 1]); + } + + for i in (0..n - 1).rev() { + suf[i] = suf[i + 1].max(start_time[i + 1] - end_time[i]); + } + + let mut ans = 0; + for i in 0..n { + let l = if i == 0 { 0 } else { end_time[i - 1] }; + let r = if i == n - 1 { + event_time + } else { + start_time[i + 1] + }; + let w = end_time[i] - start_time[i]; + ans = ans.max(r - l - w); + + if i > 0 && pre[i - 1] >= w { + ans = ans.max(r - l); + } else if i + 1 < n && suf[i + 1] >= w { + ans = ans.max(r - l); + } + } + + ans + } +} diff --git a/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.ts b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.ts new file mode 100644 index 0000000000000..64bcb78099427 --- /dev/null +++ b/solution/3400-3499/3440.Reschedule Meetings for Maximum Free Time II/Solution.ts @@ -0,0 +1,33 @@ +function maxFreeTime(eventTime: number, startTime: number[], endTime: number[]): number { + const n = startTime.length; + const pre: number[] = Array(n).fill(0); + const suf: number[] = Array(n).fill(0); + + pre[0] = startTime[0]; + suf[n - 1] = eventTime - endTime[n - 1]; + + for (let i = 1; i < n; i++) { + pre[i] = Math.max(pre[i - 1], startTime[i] - endTime[i - 1]); + } + + for (let i = n - 2; i >= 0; i--) { + suf[i] = Math.max(suf[i + 1], startTime[i + 1] - endTime[i]); + } + + let ans = 0; + for (let i = 0; i < n; i++) { + const l = i === 0 ? 0 : endTime[i - 1]; + const r = i === n - 1 ? eventTime : startTime[i + 1]; + const w = endTime[i] - startTime[i]; + + ans = Math.max(ans, r - l - w); + + if (i > 0 && pre[i - 1] >= w) { + ans = Math.max(ans, r - l); + } else if (i + 1 < n && suf[i + 1] >= w) { + ans = Math.max(ans, r - l); + } + } + + return ans; +}