455. Assign Cookies

Leetcode 问题: 455. Assign Cookies
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题目

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.

传入两个阵列，第一个 小孩阵列，每个数字代表那个小孩 想要的饼乾数量

[1,3,5] 代表

小孩索引 0 1 2
想要的饼乾数量 1 3 5

第二个阵列代表 饼乾盘阵列，每个数字代表 那一个盘子有几个饼乾

[3,5,7] 代表

饼乾盘索引 0 1 2
有多少饼乾 3 5 7

目标是要尽可能将所有小孩餵饱，满足他想要的饼乾，并找出最多能满足几个小孩

Example

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.

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.

答案

  • 尽量用最少的饼乾数量餵饱需求最少的小孩，所以要先餵饱满足度较低的小孩

JavaScript

  1. 将 小孩阵列 与 饼乾盘阵列 由小到大排序
    • 确保 小孩阵列 前面都是满足度较低的小孩
    • 确保 饼乾盘阵列 前面都是饼乾数较少的盘子
  2. 设定 小孩检查指标 到第一个满足度较低的小孩索引 0 并 设定 饼乾盘检查指标 到第一个饼乾数最少的饼乾盘索引 0
    • 当目前 小孩检查指标 的小孩能够满足，后面的小孩才有可能满足
    • 当目前 小孩检查指标 无法满足，后面的小孩也不用检查，肯定吃不饱
  3. 当 小孩检查指标 的小孩需要的饼乾，是 饼乾盘检查指标 的饼乾数可以满足的话
    • 找到一个可以餵饱的小孩了
    • 继续检查下一个小孩
    • 继续用下一个饼乾盘检查是否能够餵饱小孩
  4. 当 小孩检查指标 的小孩需要的饼乾，在 饼乾盘检查指标 的饼乾数无法满足
    • 继续找下一个饼乾盘，看后面的饼乾盘有没有足够的数量可以餵饱小孩
/**
 * @param {number[]} childrenList
 * @param {number[]} cookieList
 * @return {number}
 */
var findContentChildren = function(childrenList, cookieList) {
    // 将小孩需要的饼乾数量，依照小到大排序
    childrenList.sort((a, b) => {
        return a - b;
    });

    // 将拥有饼乾盘子数量，依照小到大排序
    cookieList.sort((a, b) => {
        return a - b;
    });

    // 小孩检查指标
    let childPointer = 0;
    // 饼乾盘检查指标
    let cookiePointer = 0;

    while (childPointer < childrenList.length && cookiePointer < cookieList.length) {
        // 当还没有检查完所有小孩，且也还没检查完所有饼乾盘子，继续检查
        if (childrenList[childPointer] <= cookieList[cookiePointer]) {
            // 当目前的饼乾盘，可以餵饱小孩，继续找下一个
            childPointer++;
            cookiePointer++;
        } else {
            // 当目前的饼乾盘，无法餵饱小孩，继续找下一个
            cookiePointer++;
        }
    }

    return childPointer;
};

参考资料