1.LeetCode刷题For Swift·11. Contai

1、原题

Given n non-negative integers a1, a2, ..., an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of the line i is at (i, ai) and (i, 0). Find two lines, which, together with the x-axis forms a container, such that the container contains the most water.

Notice that you may not slant the container.

Example 1:

Input: height = [1,8,6,2,5,4,8,3,7]
Output: 49
Explanation: The above vertical lines are represented by array [1,8,6,2,5,4,8,3,7]. In this case, the max area of water (blue section) the container can contain is 49.

Example 2:

Input: height = [1,1]
Output: 1

Example 3:

Input: height = [4,3,2,1,4]
Output: 16

Example 4:

Input: height = [1,2,1]
Output: 2

2、思路

3、代码

class Solution {
    func maxArea(_ height: [Int]) -> Int {
        // 定义最大面积
        var max = 0
        // 使用首尾逼近的方法
        var i = 0
        var j = height.count - 1
        // 定义需要的最小高度
        var minHeight = 0
        // 循环逼近
        while i < j {
            // 得出每次的最小高度
            if height[i] < height[j] {
                minHeight = height[i]
                // 左边的高度最小，就将左边的边界右移一位
                i+=1 
            } else {
                minHeight = height[j]
                // 右边的高度最小，就将右边的边界左移一位
                j-=1
            }
            // 计算面积,因为最小的高度才是决定面积的
            let area = (j - i + 1) * minHeight
            // 比较得出最大面积
            max = max > area ? max : area
        }
        return max
    }
}