11. Container With Most Water.cpp

/*
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 and n is at least 2.





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:

Input: [1,8,6,2,5,4,8,3,7]
Output: 49


Solution using two pointers,
it can be done with brute force
*/
class Solution {
public:
    int maxArea(vector<int>& height) {
        int res = 0, i = 0, j = height.size() - 1;
        while ( i < j )
        {
            int h = min( height[i], height[j] );
            res = max( res, h * ( j - i ) );
            while ( i < j && h == height[i] ) ++i;
            while ( i < j && h == height[j] ) --j;
        }
        return res;
    }
};