Assign Cookies

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.

Solution:

class Solution {
    public int findContentChildren(int[] g, int[] s) {
        TreeMap<Integer, Integer> map = new TreeMap();
        for (int c : s) {
            map.put(c, map.getOrDefault(c, 0) + 1);
        }
        int count = 0;
        for (int i : g) {
            Integer c = map.ceilingKey(i);
            if (c != null) {
                map.put(c, map.get(c) - 1);
                if (map.get(c) == 0) map.remove(c);
                count ++;
            }
        }
        return count;
    }
}