740. Delete and Earn

Given an array `nums` of integers, you can perform operations on the array.

In each operation, you pick any `nums[i]` and delete it to earn `nums[i]` points. After, you must delete every element equal to `nums[i] - 1` or `nums[i] + 1`.

You start with `0` points. Return the maximum number of points you can earn by applying such operations.

Example 1:

```Input: nums = [3,4,2]
Output: 6
Explanation: Delete 4 to earn 4 points, consequently 3 is also deleted.
Then, delete 2 to earn 2 points.
6 total points are earned.
```

Example 2:

```Input: nums = [2,2,3,3,3,4]
Output: 9
Explanation: Delete 3 to earn 3 points, deleting both 2's and the 4.
Then, delete 3 again to earn 3 points, and 3 again to earn 3 points.
9 total points are earned.
```

Constraints:

• `1 <= nums.length <= 2 * 104`
• `1 <= nums[i] <= 104`

740. Delete and Earn
``````struct Solution;

impl Solution {
fn delete_and_earn(nums: Vec<i32>) -> i32 {
let n = 10001;
let mut sum: Vec<i32> = vec![0; n];
let mut dp: Vec<i32> = vec![0; n];
for x in nums {
sum[x as usize] += x;
}
dp[1] = sum[1];
for i in 2..n {
dp[i] = i32::max(sum[i] + dp[i - 2], dp[i - 1]);
}
dp[n - 1]
}
}

#[test]
fn test() {
let nums = vec![3, 4, 2];
let res = 6;
assert_eq!(Solution::delete_and_earn(nums), res);
let nums = vec![2, 2, 3, 3, 3, 4];
let res = 9;
assert_eq!(Solution::delete_and_earn(nums), res);
}
``````