【leetcode】1090. Largest Values From Labels

题目如下：

We have a set of items: the i-th item has value values[i] and label labels[i].

Then, we choose a subset S of these items, such that:

|S| <= num_wanted

For every label L, the number of items in Swith label L is <= use_limit.

Return the largest possible sum of the subset S.
Example 1:
Input: values = [5,4,3,2,1], labels = [1,1,2,2,3], num_wanted = 3, use_limit = 1

Output: 9

Explanation: The subset chosen is the first, third, and fifth item.
Example 2:
Input: values = [5,4,3,2,1], labels = [1,3,3,3,2], num_wanted = 3, use_limit = 2

Output: 12

Explanation: The subset chosen is the first, second, and third item.
Example 3:
Input: values = [9,8,8,7,6], labels = [0,0,0,1,1], num_wanted = 3, use_limit = 1

Output: 16

Explanation: The subset chosen is the first and fourth item.
Example 4:
Input: values = [9,8,8,7,6], labels = [0,0,0,1,1], num_wanted = 3, use_limit = 2

Output: 24

Explanation: The subset chosen is the first, second, and fourth item.
Note:

1 <= values.length == labels.length <= 20000

0 <= values[i], labels[i] <= 20000

1 <= num_wanted, use_limit <= values.length

解题思路：贪心算法。每次取values中的最大值，如果对应labels没有超过限制，那么表示最大值可取；否则继续判断次大值。

代码如下：

class Solution(object):

    def largestValsFromLabels(self, values, labels, num_wanted, use_limit):

        """

        :type values: List[int]

        :type labels: List[int]

        :type num_wanted: int

        :type use_limit: int

        :rtype: int

        """

        res = 0

        def cmpf(v1,v2):

            if v1[0] - v2[0] != 0:

                return v2[0] - v1[0]

            return v2[1] - v1[1]

        val_list = sorted(zip(values,labels),cmp=cmpf)

        dic = {}

        inx = 0

        while num_wanted > 0 and inx < len(val_list):

            v,l = val_list[inx]

            if l not in dic or dic[l] < use_limit:

                res += v

                dic[l] = dic.setdefault(l,0) + 1

                num_wanted -= 1

            inx += 1

        return res

巴特西

【leetcode】1090. Largest Values From Labels

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