Leetcode: 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 1: Greedy, Time:O(nlogn)

Just assign the cookies starting from the child with less greediness to maximize the number of happy children .

public class Solution {
    public int findContentChildren(int[] g, int[] s) {
        Arrays.sort(g);
        Arrays.sort(s);
        int i = 0;
        for (int j=0; i<g.length && j<s.length; j++) {
            if (g[i] <= s[j]) i++;
        }
        return i;
    }
}

Solution 2: Greedy + TreeMap,   Time: O(nlogm), n, m are the size of two arrays respectively

public class Solution {
    public int findContentChildren(int[] g, int[] s) {
        TreeMap<Integer, Integer> map = new TreeMap<Integer, Integer>();
        int res = 0;
        for (int size : s) {
            map.put(size, map.getOrDefault(size, 0)+1);
        }

        for (int greed : g) {
            if (map.ceilingKey(greed) != null) {
                res++;
                int value = map.ceilingKey(greed);
                map.put(value, map.get(value)-1);
                if (map.get(value) == 0) map.remove(value);
            }
        }
        return res;
    }
}