CC-20 : Search second largest number.

Description:

Given an input array, find the second largest number in the array.

Test cases and expected outputs:

Input Parameters	Expected outputs
Array: 3, 22, 44, 67, 77, 96, 122, 144, 201,	Second largest number is 144

Pseudocode:

secondLargest(nums[]):

Integer array named nums is received as input parameters.

Set integer variable l1 to -1, we will use this variable to store largest number.

Set integer variable l2 to -1, , we will use this variable to store second largest number.

Iterate through nums using a for loop using idx as loop variable starting from 0 upto nums.length:

If (nums[idx] > l1) then:

Set l2=l1.

Set l1=nums[idx].

Else if nums[idx] < l1 and nums[idx]>l2 then:

Set l2=nums[idx].

Return l2.

Code:

public int secondLargest(int[] nums){
	int l1 =-1;
	int l2 =-1;
	for (int idx=0; idx < nums.length; idx++) {
		if (nums[idx] > l1) {
			l2=l1;
			l1=nums[idx];			
		} else if ((nums[idx] < l1)&&(nums[idx]> l2)){
			l2=nums[idx];
		}
	}
	return l2;
}

Click here to download and run code and test cases !

Below fully running code can be copied and run on Eclipse or other Java IDEs. Refer the classname in code below. If the class name below is "A", save the code below to a file named A.java before running it. Be sure to try your own test cases to enhance your understanding ! You can also tweak the code to optimize or add enhancements and custom features.

public class SearchSecondLargest {

public int secondLargest(int[] nums){
	int l1 =-1;
	int l2 =-1;
	for (int idx=0; idx < nums.length; idx++) {
		if (nums[idx] > l1) {
			l2=l1;
			l1=nums[idx];			
		} else if ((nums[idx] < l1)&&(nums[idx]> l2)){
			l2=nums[idx];
		}
	}
	return l2;
}


public static void main(String[] args) {
	/***********************
	 Test cases given below:
	 **********************/
	int retVal;
	try {
	
	SearchSecondLargest search=new SearchSecondLargest();
	int[] nums= { 3,22,44,67,77,96,122, 144, 201};
	
	retVal=search.secondLargest(nums);
	
	System.out.println("\nArray:");
	int arrayIndex=0;
	for (arrayIndex=0; arrayIndex < nums.length; arrayIndex++) {
		System.out.print(nums[arrayIndex]+", ");		
	} 
	
	System.out.println("\n\nSecond largest number is "+ retVal);	
	
	
	
	}catch (Exception exception) {
		System.out.print("Exception: "+ exception);
		exception.printStackTrace();
	}
		
}

}