Problem

Givennnon-negative integersa1,a2, ...,an, where each represents a point at coordinate (i,ai).nvertical lines are drawn such that the two endpoints of lineiis at (i,ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.

Note: You may not slant the container andnis at least 2.

找出两条线所形成的最大面积

暴力思路

• 两层for循环
• 时间复杂度： O(n ^ 2)

思路（Two Pointer）

• maintain a result variable, a left pointer and a right pointer
• update result
• if [left] < [right], left++
• else, right--

    public int maxArea(int[] height) {
        if (height == null || height.length == 0) return 0;

        int l = 0;
        int r = height.length - 1;
        int res = 0;

        while (l < r) {
            res = Math.max(res, Math.min(height[l], height[r]) * (r - l));
            if (height[l] < height[r]) {
                l++;
            } else {
                r--;
            }
        }
        return res;
    }