Container With Most Water

Medium

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 the line i is at (i, ai) and (i, 0). Find two lines, which, together with the x-axis forms a container, such that the container contains the most water.

Example:

Input: height = [1,8,6,2,5,4,8,3,7]
Output: 49
Explanation: 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.

Solution


Two Pointer Approach

class Solution {
    public int maxArea(int[] height) {
        
        if(height == null || height.length == 0){
            return 0;
        }
        int l = 0;
        int r = height.length -1;
        int max_area = 0;
        while( l < r){
            int h = Math.min(height[l], height[r]);
            int w = (r-l);
            int cur_area = (h * w);
            max_area = Math.max(cur_area, max_area);
            if(height[l] < height[r]){
                l++;
            }else{
                r--;
            }
        }
        return max_area;
    }
}

Complexity Analysis

  • Time Complexity : O(n). Single pass.
  • Space Complexity : O(1). Constant space is used.

Categories: Array

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