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:

1 | Input: nums = [3, 4, 2] |

Example 2:

1 | Input: nums = [2, 2, 3, 3, 3, 4] |

Note:

The length of nums is at most 20000.

Each element nums[i] is an integer in the range [1, 10000].

动态规划问题，状态转移方程

dp[i] = max(dp[i - 1], dp[i - 2] + a[i])

初值

dp[1] = a[1]

dp[2] = max(dp[1], a[2] * 2)

1 | class Solution { |