## Find GCD of Two Numbers using Recursion – Java Code

Write a Java program to find GCD of two numbers using Recursion. Given two input integers, we have to write a code to find GCD of two numbers using recursion. For this program, I assume you are familiar with the concept of recursion. If you don’t know about recursion then check my previous post on recursion vs iteration.

## Find First Non-repeating Character in a String – Java Code

Write a java program to find first non-repeating character in a string. Given an input string, Write a java code to find first non-repeating character in a string.

For example –

i) Input string – java
Output – j (j is the first non-repeating character in a string)

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ii) Input string – web rewrite
Output – b (b is the first non-repeating character in a string)

## PHP Code to Find Second Largest Number in Array

Write a PHP code to find second largest number in array. Given an unsorted array, we have to write a PHP program to find the second largest number in an array.

Apart from solving this problem. We have to focus on time complexity. As the time complexity of an algorithm is very important in terms of an interview.

## Reverse a String in PHP without using strrev() Method

Write a script to reverse a string in PHP without using strrev() method. In PHP, we can reverse a string easily using strrev() method. But think how will you reverse a string without using an inbuilt strrev() method.

## Find Largest Sum Contiguous Subarray – Kadane’s algorithm

Write a program to find largest sum contiguous subarray. Given an array of N elements, find the maximum possible sum of a contiguous subarray. An array can contain both positive and negative values.

For example –

Let’s take an array whose values are { 1, 2, -5, 4, 3, 8 , 5 }

The maximum sum of a subarray in this array is 20.  And the subarray is (4, 3, 8, 5).