455. Assign Cookies (Easy)

Assume you are an awesome parent and want to give your children some cookies. But, you should give each child at most one cookie. Each child i has a greed factor gi, which is the minimum size of a cookie that the child will be content with; and each cookie j has a size sj. If sj >= gi, we can assign the cookie j to the child i, and the child i will be content. Your goal is to maximize the number of your content children and output the maximum number.

Note:
You may assume the greed factor is always positive. 
You cannot assign more than one cookie to one child.

Example 1:

Input: [1,2,3], [1,1]

Output: 1

Explanation: You have 3 children and 2 cookies. The greed factors of 3 children are 1, 2, 3. 
And even though you have 2 cookies, since their size is both 1, you could only make the child whose greed factor is 1 content.
You need to output 1.

 

Example 2:

Input: [1,2], [1,2,3]

Output: 2

Explanation: You have 2 children and 3 cookies. The greed factors of 2 children are 1, 2. 
You have 3 cookies and their sizes are big enough to gratify all of the children, 
You need to output 2.

思路：通过贪心算法（Greedy Algorithm），优先满足比较容易满足的孩子，并且尽可能的分发饼干；
1.首先对g、s进行排序；
2.令指针i、j分别指向g、s的末尾；
3.若g[i]<=s[j]，则计数器cnt加1，j减1，将j号cookie分给i号孩子，并指向下一个更小的cookie，i减1，指向下一个greedy factor更小的孩子；

 

class Solution():
    def findContentChildren(self, g, s):
        """
        :type g: List[int]
        :type s: List[int]
        :rtype: int
        """
        cnt = 0
        i, j = len(g) - 1, len(s) - 1
        g, s = sorted(g), sorted(s)
        while min(i, j) >= 0:
            if g[i] <= s[j]:
                cnt += 1
                j -= 1
            i -= 1
        return cnt