455. Assign Cookies

1. Description

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 g[i], which is the minimum size of a cookie that the child will be content with; and each cookie j has a size s[j]. If s[j] >= g[i], 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.

2. Example

Example 1

Input: g = [1,2,3], s = [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: g = [1,2], s = [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.

3. Constraints

• 1 <= g.length <= $3 * 10^4$
• 0 <= s.length <= $3 * 10^4$
• 1 <= g[i], s[j] <= 2$^{31}$ - 1

4. Solutions

Sorting

m = i_childrenSize.size(), n = i_cookiesSize.size())
Time complexity: O($mlog_2m + nlog_2n$)
Space complexity: O(1)

 1
 2
 3
 4
 5
 6
 7
 8
 9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24

// greedy

class Solution
{
public:
    // int findContentChildren(vector<int>& g, vector<int>& s)
    int findContentChildren(vector<int> &i_childrenSize, vector<int>& i_cookiesSize)
    {
        sort(i_childrenSize.begin(), i_childrenSize.end());
        sort(i_cookiesSize.begin(), i_cookiesSize.end());

        int result = 0;
        for(int childIndex = 0, cookieIndex = 0; childIndex < i_childrenSize.size() && cookieIndex < i_cookiesSize.size(); cookieIndex++)
        {
            if(i_childrenSize[childIndex] <= i_cookiesSize[cookieIndex])
            {
                result++;
                childIndex++;
            }
        }

        return result;
    }
};