### Heap Sort Algorithm

This is another very useful sorting algorithm based on Heap data structure. Read…

September 13, 2019

Given n non-negative integers a1, a2, …, an , where each represents a point at coordinate (i, ai). n vertical lines are drawn such that the two endpoints of line i is at (i, ai) and (i, 0). Find two lines, which together with x-axis forms a container, such that the container contains the most water.

Note: You may not slant the container and n is at least 2.

A simple brute force algorithm is what you can start with.

```
public int maxArea(int[] height) {
int max = 0;
int l = height.length;
for (int i=0; i<l; i++) {
for (int j=i+1; j<l; j++) {
int area = (j-i) * Math.min(height[i], height[j]);
if (area > max) {
max = area;
}
}
}
return max;
}
```

Lets think of optimizing this computation. What if we start with max range, and move either left or right. Since, lower height determines the area. And, we can move greedily towards point with high height. And, compare the area.

We can start with left and right pointer, calculate area. Then we can move towards point with higher height. i.e. the side which is having less height, we should move that pointer. Example: If left pointer value is less, move it right. Similarly, if right pointer value is less than right, move it left.

```
public int maxArea(int[] height) {
int l = height.length;
int result = 0;
int i=0;
int j = l-1;
while (i < j) {
int area = (j-i) * Math.min(height[i], height[j]);
if (result < area) {
result = area;
}
if (height[i] < height[j]) {
i++;
}
else j--;
}
return result;
}
```

This is another very useful sorting algorithm based on Heap data structure. Read…

Problem Implement an algorithm to determine if a string has all the characters…

Problem Statement Given an array of integers, return indices of the two numbers…

Big-O notation In simpler terms, its kind of a unit to measure how efficient an…

This algorithm is very efficient one, and is classic example of Divide and…

Problem Statement Given an array of integers, find if the array contains any…

Problem Statement You are given a string text of words that are placed among…

Problem Statement You are given a rows x cols matrix grid. Initially, you are…

Problem Statement Given a string s, return the maximum number of unique…

Problem The Leetcode file system keeps a log each time some user performs a…

Problem Statement Replace all spaces in a string with ‘%20’ (three characters…

Problem Implement an algorithm to determine if a string has all the characters…