Container With Most Water - Leet Code

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

Java Solution :

class Solution {
    public int maxArea(int[] height) {
        int max = Integer.MIN_VALUE;
        int i =0;
        int j = height.length-1;
        while(i<j){
            int min = Math.min(height[i],height[j]);
            max = Math.max(max, (j-i)*min);
            if(height[i]<height[j]){
                i++;
            }else {
                j--;
            }
        }
        return max;
    }
}

Complexity Analysis


Time complexity : $O(n)$. Single pass.


Space complexity : $O(1)$. Constant space is used.