11. Container With Most Water

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 line i is 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.

Similar: 42. Trapping Rain Water

public class Solution {
    public int maxArea(int[] height) {
        if (height.length < 2) return 0;
        int l = 0, r = height.length-1;
        int max = 0;
        while (l < r) {
            int lomax = height[l];
            int himax = height[r];
            max = Math.max(max, (r - l) * (lomax < himax ? lomax : himax));
            
            if (height[l] < height[r])
                while (l < r && height[l] <= lomax) l++; // will change l at least one step
            else while (l < r && height[r] <= himax) r--;
        }
        
        return max;
    }
}