【LeetCode】455. Assign Cookies 分發餅乾（Medium）（JAVA）每日一題

【LeetCode】455. Assign Cookies 分發餅乾（Medium）（JAVA）

題目地址: https://leetcode.com/problems/assign-cookies/

題目描述：

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.

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.

Constraints:

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

題目大意

假設你是一位很棒的家長，想要給你的孩子們一些小餅乾。但是，每個孩子最多隻能給一塊餅乾。

對每個孩子 i，都有一個胃口值 g[i]，這是能讓孩子們滿足胃口的餅乾的最小尺寸；並且每塊餅乾 j，都有一個尺寸 s[j] 。如果 s[j] >= g[i]，我們可以將這個餅乾 j 分配給孩子 i ，這個孩子會得到滿足。你的目標是儘可能滿足越多數量的孩子，並輸出這個最大數值。

解題方法

1. 採用排序+貪心
2. 先對兩個陣列 g 和 s 分別排序
3. 遍歷 g 陣列，找出在 s 中剛好比 g[i] 大的元素，然後分給 g[i] 為 s[j] 的餅乾，下次就從 j + 1 開始搜尋

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

執行耗時:8 ms,擊敗了89.07% 的Java使用者
記憶體消耗:38.9 MB,擊敗了95.31% 的Java使用者

歡迎關注我的公眾號，LeetCode 每日一題更新