Container With Most Water

Question

Given an array where each element represents the height of a vertical line on the x-axis, you need to find two lines that together with the x-axis form a container that holds the most water.

You may not slant the container – only vertical sides are allowed.

Example

Input: [1, 8, 9, 2, 1, 8, 2, 0, 7]

Output: 49

Explanation: Max area is formed between height 8 (index 1) and height 7 (index 8): min(8, 7) × (8 - 1) = 7 × 7 = 49.

Input: [1, 1]

Output: 1

Explanation: 1 × 1 = 1

Visual

My Notes

Use two pointers: one at the start, one at the end.
At each step, calculate the area formed by the shorter line.
Move the pointer pointing to the shorter line inward.
Keep track of the maximum area seen so far.
Time complexity: O(n), Space complexity: O(1)

package main

import (
	"fmt"
)

func main() {
	result := maxArea([]int{8,7,2,1})
	fmt.Println(result)
}

func maxArea(height []int) int {
	i, j, minHeight, currentArea, maxArea := 0, len(height) - 1, 0, 0, 0

	for i < j {
		if height[i] < height[j] {
			minHeight = height[i]
		} else {
			minHeight = height[j]
		}
		currentArea = (j - i) * minHeight

		if maxArea < currentArea {
			maxArea = currentArea
		}
		if height[i] < height[j] {
			i++
		} else {
			j--
		}
	}

	return maxArea
}