1402. Reducing Dishes

Hard

A chef has collected data on the satisfaction level of his n dishes. Chef can cook any dish in 1 unit of time.

Like-time coefficient of a dish is defined as the time taken to cook that dish including previous dishes multiplied by its satisfaction level i.e. time[i] * satisfaction[i].

Return the maximum sum of like-time coefficient that the chef can obtain after dishes preparation.

Dishes can be prepared in any order and the chef can discard some dishes to get this maximum value.

Example 1:

Input: satisfaction = [-1,-8,0,5,-9]
Output: 14
Explanation: After Removing the second and last dish, the maximum total like-time coefficient will be equal to (-1*1 + 0*2 + 5*3 = 14).
Each dish is prepared in one unit of time.

Example 2:

Input: satisfaction = [4,3,2]
Output: 20
Explanation: Dishes can be prepared in any order, (2*1 + 3*2 + 4*3 = 20)

Example 3:

Input: satisfaction = [-1,-4,-5]
Output: 0
Explanation: People do not like the dishes. No dish is prepared.

Constraints:

• n == satisfaction.length

• 1 <= n <= 500

• -1000 <= satisfaction[i] <= 1000

解題

func maxSatisfaction(satisfaction []int) int {
    l := len(satisfaction)
    res, sum, psum := 0, 0, 0

    sort.Ints(satisfaction)

    for i:=l-1; i>=0; i-- {
        psum += satisfaction[i]
        sum += psum
        res = max(res, sum)
    }

    return res
}

func max(a, b int) int {
    if a > b { return a }
    return b
}