11. Container With Most Water | Leetcode Solution

11. Container With Most Water

You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the ith line are (i, 0) and (i, height[i]).

Find two lines that together with the x-axis form a container, such that the container contains the most water.

Return the maximum amount of water a container can store.

Notice that you may not slant the container.

Example 1:

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.

Example 2:

Input: height = [1,1]
Output: 1

Constraints:

n == height.length
2 <= n <= 105
0 <= height[i] <= 104

Solution

we will do this using two pointer approach. we will make a start pointer and an end pointer. The start will be at 0 and the end will be at the last position. Now we will find the area in that container that will be

area=distance between them x minimum of heights of start and end

Now we will move the pointer which is smaller so that we can get a better answer than this.

We will do this until start<end.

Here is the code -

class Solution {
public:
    int maxArea(vector<int>& v) {
        int st=0;
        int end=v.size()-1;
        int ans=0;
        while(st<end){
            ans=max(ans,abs(st-end)*(min(v[st],v[end])));
            if(v[st]>v[end]){
                end--;
            }
            else if(v[st]<v[end]){
                st++;
            }
            else{
                st++;
                end--;
            }
        }
        return ans;
    }
};