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‎Problemset/1425-Constrained Subsequence Sum/README.md

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# 1425. Constrained Subsequence Sum
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Given an integer array `nums` and an integer `k`, return the maximum sum of a **non-empty** subsequence of that array such that for every two **consecutive** integers in the subsequence, `nums[i]` and `nums[j]`, where `i < j`, the condition `j - i <= k` is satisfied.
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A *subsequence* of an array is obtained by deleting some number of elements (can be zero) from the array, leaving the remaining elements in their original order.
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#### Example 1:
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<pre>
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<strong>Input:</strong> nums = [10,2,-10,5,20], k = 2
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<strong>Output:</strong> 37
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<strong>Explanation:</strong> The subsequence is [10, 2, 5, 20].
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</pre>
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#### Example 2:
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<pre>
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<strong>Input:</strong> nums = [-1,-2,-3], k = 1
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<strong>Output:</strong> -1
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<strong>Explanation:</strong> The subsequence must be non-empty, so we choose the largest number.
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</pre>
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#### Example 3:
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<pre>
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<strong>Input:</strong> nums = [10,-2,-10,-5,20], k = 2
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<strong>Output:</strong> 23
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<strong>Explanation:</strong> The subsequence is [10, -2, -5, 20].
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</pre>
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#### Constraints:
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* <code>1 <= k <= nums.length <= 10<sup>5</sup></code>
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* <code>-10<sup>4</sup> <= nums[i] <= 10<sup>4</sup></code>
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## Solutions (Rust)
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### 1. Solution
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```Rust
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use std::collections::VecDeque;
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impl Solution {
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pub fn constrained_subset_sum(nums: Vec<i32>, k: i32) -> i32 {
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let k = k as usize;
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let mut deque = VecDeque::new();
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let mut ret = *nums.iter().max().unwrap();
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for i in 0..nums.len() {
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if i - deque.front().unwrap_or(&(i, 0)).0 > k {
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deque.pop_front();
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}
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let x = nums[i] + deque.front().unwrap_or(&(0, 0)).1;
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if x > 0 {
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while deque.back().unwrap_or(&(0, i32::MAX)).1 <= x {
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deque.pop_back();
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}
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deque.push_back((i, x));
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ret = ret.max(x);
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}
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}
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ret
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}
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}
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```

‎Problemset/1425-Constrained Subsequence Sum/README_CN.md

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# 1425. 带限制的子序列和
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给你一个整数数组 `nums` 和一个整数 `k` ，请你返回 **非空** 子序列元素和的最大值，子序列需要满足：子序列中每两个 **相邻** 的整数 `nums[i]` 和 `nums[j]` ，它们在原数组中的下标 `i` 和 `j` 满足 `i < j` 且 `j - i <= k` 。
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数组的子序列定义为：将数组中的若干个数字删除（可以删除 0 个数字），剩下的数字按照原本的顺序排布。
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#### 示例 1:
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<pre>
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<strong>输入:</strong> nums = [10,2,-10,5,20], k = 2
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<strong>输出:</strong> 37
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<strong>解释:</strong> 子序列为 [10, 2, 5, 20] 。
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</pre>
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#### 示例 2:
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<pre>
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<strong>输入:</strong> nums = [-1,-2,-3], k = 1
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<strong>输出:</strong> -1
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<strong>解释:</strong> 子序列必须是非空的，所以我们选择最大的数字。
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</pre>
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#### 示例 3:
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<pre>
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<strong>输入:</strong> nums = [10,-2,-10,-5,20], k = 2
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<strong>输出:</strong> 23
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<strong>解释:</strong> 子序列为 [10, -2, -5, 20] 。
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</pre>
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#### 提示:
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* <code>1 <= k <= nums.length <= 10<sup>5</sup></code>
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* <code>-10<sup>4</sup> <= nums[i] <= 10<sup>4</sup></code>
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## 题解 (Rust)
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### 1. 题解
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```Rust
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use std::collections::VecDeque;
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impl Solution {
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pub fn constrained_subset_sum(nums: Vec<i32>, k: i32) -> i32 {
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let k = k as usize;
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let mut deque = VecDeque::new();
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let mut ret = *nums.iter().max().unwrap();
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for i in 0..nums.len() {
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if i - deque.front().unwrap_or(&(i, 0)).0 > k {
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deque.pop_front();
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}
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let x = nums[i] + deque.front().unwrap_or(&(0, 0)).1;
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if x > 0 {
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while deque.back().unwrap_or(&(0, i32::MAX)).1 <= x {
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deque.pop_back();
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}
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deque.push_back((i, x));
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ret = ret.max(x);
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}
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}
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ret
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}
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}
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```

‎Problemset/1425-Constrained Subsequence Sum/Solution.rs

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use std::collections::VecDeque;
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impl Solution {
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pub fn constrained_subset_sum(nums: Vec<i32>, k: i32) -> i32 {
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let k = k as usize;
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let mut deque = VecDeque::new();
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let mut ret = *nums.iter().max().unwrap();
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for i in 0..nums.len() {
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if i - deque.front().unwrap_or(&(i, 0)).0 > k {
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deque.pop_front();
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}
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let x = nums[i] + deque.front().unwrap_or(&(0, 0)).1;
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if x > 0 {
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while deque.back().unwrap_or(&(0, i32::MAX)).1 <= x {
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deque.pop_back();
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}
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deque.push_back((i, x));
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ret = ret.max(x);
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}
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}
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ret
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}
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}

‎README.md

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[1422][1422l]|[Maximum Score After Splitting a String][1422] |![rs]
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[1423][1423l]|[Maximum Points You Can Obtain from Cards][1423] |![rs]
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[1424][1424l]|[Diagonal Traverse II][1424] |![rb]
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[1425][1425l]|[Constrained Subsequence Sum][1425] |![rs]
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[1431][1431l]|[Kids With the Greatest Number of Candies][1431] |![rs]
830831
[1432][1432l]|[Max Difference You Can Get From Changing an Integer][1432] |![rs]
831832
[1433][1433l]|[Check If a String Can Break Another String][1433] |![rs]
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[1422]:Problemset/1422-Maximum%20Score%20After%20Splitting%20a%20String/README.md#1422-maximum-score-after-splitting-a-string
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[1423]:Problemset/1423-Maximum%20Points%20You%20Can%20Obtain%20from%20Cards/README.md#1423-maximum-points-you-can-obtain-from-cards
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[1424]:Problemset/1424-Diagonal%20Traverse%20II/README.md#1424-diagonal-traverse-ii
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[1425]:Problemset/1425-Constrained%20Subsequence%20Sum/README.md#1425-constrained-subsequence-sum
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[1431]:Problemset/1431-Kids%20With%20the%20Greatest%20Number%20of%20Candies/README.md#1431-kids-with-the-greatest-number-of-candies
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[1432]:Problemset/1432-Max%20Difference%20You%20Can%20Get%20From%20Changing%20an%20Integer/README.md#1432-max-difference-you-can-get-from-changing-an-integer
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[1433]:Problemset/1433-Check%20If%20a%20String%20Can%20Break%20Another%20String/README.md#1433-check-if-a-string-can-break-another-string
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[1422l]:https://leetcode.com/problems/maximum-score-after-splitting-a-string/
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[1423l]:https://leetcode.com/problems/maximum-points-you-can-obtain-from-cards/
35923594
[1424l]:https://leetcode.com/problems/diagonal-traverse-ii/
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[1425l]:https://leetcode.com/problems/constrained-subsequence-sum/
35933596
[1431l]:https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/
35943597
[1432l]:https://leetcode.com/problems/max-difference-you-can-get-from-changing-an-integer/
35953598
[1433l]:https://leetcode.com/problems/check-if-a-string-can-break-another-string/

‎README_CN.md

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[1422][1422l]|[分割字符串的最大得分][1422] |![rs]
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[1423][1423l]|[可获得的最大点数][1423] |![rs]
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[1424][1424l]|[对角线遍历 II][1424] |![rb]
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[1425][1425l]|[带限制的子序列和][1425] |![rs]
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[1431][1431l]|[拥有最多糖果的孩子][1431] |![rs]
830831
[1432][1432l]|[改变一个整数能得到的最大差值][1432] |![rs]
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[1433][1433l]|[检查一个字符串是否可以打破另一个字符串][1433] |![rs]
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[1422]:Problemset/1422-Maximum%20Score%20After%20Splitting%20a%20String/README_CN.md#1422-分割字符串的最大得分
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[1423]:Problemset/1423-Maximum%20Points%20You%20Can%20Obtain%20from%20Cards/README_CN.md#1423-可获得的最大点数
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[1424]:Problemset/1424-Diagonal%20Traverse%20II/README_CN.md#1424-对角线遍历-ii
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[1425]:Problemset/1425-Constrained%20Subsequence%20Sum/README_CN.md#1425-带限制的子序列和
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[1431]:Problemset/1431-Kids%20With%20the%20Greatest%20Number%20of%20Candies/README_CN.md#1431-拥有最多糖果的孩子
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[1432]:Problemset/1432-Max%20Difference%20You%20Can%20Get%20From%20Changing%20an%20Integer/README_CN.md#1432-改变一个整数能得到的最大差值
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[1433]:Problemset/1433-Check%20If%20a%20String%20Can%20Break%20Another%20String/README_CN.md#1433-检查一个字符串是否可以打破另一个字符串
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[1422l]:https://leetcode.cn/problems/maximum-score-after-splitting-a-string/
35913593
[1423l]:https://leetcode.cn/problems/maximum-points-you-can-obtain-from-cards/
35923594
[1424l]:https://leetcode.cn/problems/diagonal-traverse-ii/
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[1425l]:https://leetcode.cn/problems/constrained-subsequence-sum/
35933596
[1431l]:https://leetcode.cn/problems/kids-with-the-greatest-number-of-candies/
35943597
[1432l]:https://leetcode.cn/problems/max-difference-you-can-get-from-changing-an-integer/
35953598
[1433l]:https://leetcode.cn/problems/check-if-a-string-can-break-another-string/

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