Container With Most Water

👶 The 5-Year-Old Summary

Two vertical lines with water between them. Height is the shorter line, width is the distance. Max area = height × width!

🎮 Interactive Visualizer

heights = [1,8,6,2,5,4,8,3,7]

🧠 The Brain Hack

Start with max width! Two pointers at ends, move toward center. Always move the shorter line (smaller height). Why? Width is shrinking, so we need to find a taller line to possibly increase area!

💻 The Clean Solution

def max_area(height):
    left, right = 0, len(height) - 1
    max_water = 0
    
    while left < right:
        # Calculate current area
        width = right - left
        h = min(height[left], height[right])
        max_water = max(max_water, width * h)
        
        # Move the shorter line
        if height[left] < height[right]:
            left += 1
        else:
            right -= 1
    
    return max_water

# [1,8,6,2,5,4,8,3,7] → 49 (between 8 and 7)

Time: O(n)

Space: O(1)