LeetCode 455 Assign Cookies

Posted 2020-08-24 SillyVicky

Problem:

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.

Analysis:

将M个饼干分给N个小朋友，每个小朋友有一个贪心值，要求小朋友的得到的饼干大小要大于或等于贪心值大小。

求最多有多少小朋友可以分到饼干。

Summary:

将两个数组由小到大排序，分别用指针从头至尾比较即可。

 1 class Solution {
 2 public:
 3     int findContentChildren(vector<int>& g, vector<int>& s) {
 4         int cnt = 0, glen = g.size(), slen = s.size();
 5         sort(g.begin(), g.end());
 6         sort(s.begin(), s.end());
 7         
 8         int i = 0, j = 0;
 9         while ( i < glen && j < slen) {
10             if (g[i] <= s[j]) {
11                 i++; 
12                 j++;
13                 cnt++;
14             }
15             else if (g[i] > s[j]) {
16                 j++;
17             }
18         }
19         
20         return cnt;
21     }
22 };