问题描述

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.

测试样例

1
2
3
4
5
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.
1
2
3
4
5
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.

说明

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

解题

思路

从最小的饥饿值的孩子开始，分配能满足它的最小饼干

补充：

  1. 先排序
  2. 贪心算法
  3. 时间复杂度 O(nlogn)（排序）

代码

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
import java.util.Arrays;

class Solution {
    public int findContentChildren(int[] g, int[] s) {

        // 从小到大排序
        Arrays.sort(g);
        Arrays.sort(s);
        
        // 从最小的饥饿值的孩子开始，分配能满足它的最小饼干
        int g_p = 0, s_p = 0;
        while(g_p < g.length && s_p < s.length) {
            if(s[s_p] >= g[g_p]) ++g_p;  // 第 s_p 饼干可满足第 g_p 个孩子
            ++s_p;                       // 下一个饼干
        }
        // 已满足的孩子数量
        return g_p;
    }
}