11. Container With Most Water

source: https://leetcode.com/problems/container-with-most-water/

Question

You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).

Find two lines that together with the x-axis form a container, such that the container contains the most water.

Return the maximum amount of water a container can store.

Notice that you may not slant the container.

思路

这题和42题看起来有点像，都是去接水，但是两者其实差别很大，一题是去算总共能接的水，一题是去算最优情况。但类似的是，他们都可以用双指针去做。

从初始情况开始，宽度是最大的，之后无论怎么动，宽度都是在减小。除非两者高度的较小值变大。

所以优先去移动高度较小的一边。

/**
 * @param {number[]} height
 * @return {number}
 */
var maxArea = function(height) {
    let ret = 0;
    let left = 0;
    let right = height.length - 1;
    while (left < right) {
        const width = right - left;
        const length = Math.min(height[left], height[right]);
        const volume = width * length;
        ret = Math.max(volume, ret);
        if (height[left] < height[right]) left++;
        else right--;
    }
    return ret;
};

总结

链表的while遍历方式应用很普遍。