Container With Most Water

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

Given an integer array nums, return all unique triplets [nums[i], nums[j], nums[k]] that sum to 0.

Trapping Rain Water (Two Pointers)

Given elevation map bars, compute how much water can be trapped after raining.

Dynamic Programming & AdvancedBeginner LevelStudy Time: 15 mins

Two Pointers Pattern Algorithm

The Two Pointers pattern uses two converging or fast/slow pointer indices to search pairs or process arrays in linear O(N) time.

Two Pointers Pattern Visualizer

Array loaded. Set target sum and click Find Pair to watch left/right pointers converge.

2[0]

3[1]

5[2]

8[3]

9[4]

11[5]

14[6]

18[7]

Speed:

Real-world analogy: Closing in from Both Ends

Converging Pointers

Hover over items for details

Two friends walk toward each other from opposite ends of a street until they meet at the target location.

Converging Pointers= Left pointer moves right (+1), right pointer moves left (-1).

Complexity analysis

Scenario Simulator: Dataset Size (N = 500)

Presets:

N = 10N = 10,000

Complexity Curve MapTwo Pointers Pattern: O(N) Linear Time

Hover curves to inspect classes

Time Steps (N=500)

500 steps (Linear)

O(N) Linear Time

Space Footprint

O(1) / O(N) Space

Memory growth rate as N expands.

Performance Rank

Efficient Tier

Relative efficiency rating for large N.

Operation	Time Complexity	Space Complexity
Two Pointers Loop	O(N)	O(1)

Code implementations

function twoSumSorted(arr, target) {
  let left = 0, right = arr.length - 1;
  while (left < right) {
    const sum = arr[left] + arr[right];
    if (sum === target) return [left, right];
    if (sum < target) left++;
    else right--;
  }
  return [];
}