11. Container With Most Water

Question

LeetCode Problem

You are given an integer array height of length n. There are n vertical lines drawn such that the two endpoints of the i^{th} 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. The illustration on the LeetCode page highlights the maximal blue area.

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 <= 10^{5}
• 0 <= height[i] <= 10^{4}

Solutions

int maxArea(vector<int> &height) {
    int left = 0;
    int right = height.size() - 1;
    if (height.size() < 2) {
        return 0;
    }
    int max_area = 0;
    while (left < right) {
        int area = min(height[left], height[right]) * (right - left);
        max_area = max(area, max_area);
        if (height[left] < height[right]) {
            ++left;
        } else {
            --right;
        }
    }
    return max_area;
}