2099. Find Subsequence of Length K With the Largest Sum

You are given an integer array `nums` and an integer `k`. You want to find a subsequence of `nums` of length `k` that has the largest sum.

Return any such subsequence as an integer array of length `k`.

A subsequence is an array that can be derived from another array by deleting some or no elements without changing the order of the remaining elements.

Example 1:

```Input: nums = [2,1,3,3], k = 2
Output: [3,3]
Explanation:
The subsequence has the largest sum of 3 + 3 = 6.```

Example 2:

```Input: nums = [-1,-2,3,4], k = 3
Output: [-1,3,4]
Explanation:
The subsequence has the largest sum of -1 + 3 + 4 = 6.
```

Example 3:

```Input: nums = [3,4,3,3], k = 2
Output: [3,4]
Explanation:
The subsequence has the largest sum of 3 + 4 = 7.
Another possible subsequence is [4, 3].
```

Constraints:

• `1 <= nums.length <= 1000`
• `-105 <= nums[i] <= 105`
• `1 <= k <= nums.length`

2099. Find Subsequence of Length K With the Largest Sum
``````struct Solution;

#[derive(Clone)]
struct Pair {
value: i32,
index: usize,
}

impl Solution {
fn max_subsequence(nums: Vec<i32>, k: i32) -> Vec<i32> {
let n = nums.len();
let mut pairs: Vec<Pair> = vec![];
for i in 0..n {
pairs.push(Pair {
value: nums[i],
index: i,
});
}
pairs.sort_by_key(|p| p.value);
let k = k as usize;
let mut k_pairs: Vec<Pair> = vec![];
for i in 0..k {
k_pairs.push(pairs[n - k + i].clone());
}
k_pairs.sort_by_key(|p| p.index);
let mut res = vec![];
for i in 0..k {
res.push(k_pairs[i].value);
}
res
}
}

#[test]
fn test() {
let nums = vec![2, 1, 3, 3];
let k = 2;
let res = vec![3, 3];
assert_eq!(Solution::max_subsequence(nums, k), res);
let nums = vec![-1, -2, 3, 4];
let k = 3;
let res = vec![-1, 3, 4];
assert_eq!(Solution::max_subsequence(nums, k), res);
let nums = vec![3, 4, 3, 3];
let k = 2;
let res = vec![4, 3];
assert_eq!(Solution::max_subsequence(nums, k), res);
}
``````