LeetCode - Number of Good Pairs Solution - The Coding Shala

Home >> LeetCode >> Number of Good Pairs
In this post, we will learn how to solve LeetCode's Number of Good Pairs problem and will implement its solution in Java.

Number of Good Pairs

Given an array of integers nums. A pair (i,j) is called good if nums[i] == nums[j] and i < j. Return the number of good pairs.

Example 1:
Input: nums = [1,2,3,1,1,3]
Output: 4
Explanation: There are 4 good pairs (0,3), (0,4), (3,4), (2,5) 0-indexed.

Example 2:
Input: nums = [1,1,1,1]
Output: 6
Explanation: Each pair in the array are good.

Practice this problem on LeetCode: (Click Here).

Number of Good Pairs Java Solution

Approach 1:
Using two loops.
Time Complexity: O(n^2).

Java Program: 

class Solution {
    public int numIdenticalPairs(int[] nums) {
        int ans = 0;
        for(int i=0; i<nums.length-1; i++) {
            for(int j=i+1; j<nums.length; j++) {
                if(nums[i] == nums[j]) ans++;
            }
        }
        return ans;
    }
}


Other Posts You May Like
Please leave a comment below if you like this post or found some error, it will help me to improve my content.
By

Comments

Post a Comment

Popular Posts from this Blog

Time Complexity, Space Complexity, Asymptotic Notations - The Coding Shala

Image
Home >> Algorithms >> Time and space complexity Time Complexity, Space Complexity, and Asymptotic Notations Time complexity describes the time taken by an algorithm and space complexity describes the memory used by an algorithm. Asymptotic Notations are languages that allow us to calculate time complexity and space complexity. Big O is most commonly used for time complexity or analysis of algorithms. Time Complexity In Computer Science, the time complexity of an algorithm quantifies the amount of time taken by an algorithm to run as a function of the length of the string representing the input. The time complexity of an algorithm is commonly expressed using big O notation, which excludes coefficients and lowers order terms.[From Wikipedia] In a simple way we can say how much time our code takes to execute.  So, How to calculate the running time of an algorithm? We can have three cases to analyze an algorithm: Worst Case Average Case Best C...
Read more

LeetCode - Crawler Log Folder Solution - The Coding Shala

Home >> LeetCode >> Crawler Log Folder  In this post, we will learn how to solve LeetCode's Crawler Log Folder problem and will implement Crawler Log Folder Java Solution. Crawler Log Folder Problem The Leetcode file system keeps a log each time some user performs a change folder operation. The operations are described below: "../": Move to the parent folder of the current folder. (If you are already in the main folder, remain in the same folder). "./": Remain in the same folder. "x/": Move to the child folder named x (This folder is guaranteed to always exist). You are given a list of strings logs where logs[i] is the operation performed by the user at the ith step. The file system starts in the main folder, then the operations in logs are performed. Return the minimum number of operations needed to go back to the main folder after the change folder operations. Input: logs = ["d1/","d2/","../","d2...
Read more

Graph Representation using Adjacency Matrix - The Coding Shala

Image
Home >> Data Structures >> Graph Representation using Adjacency Matrix Graph Representation using Adjacency Matrix In this post, we will see how to represent a graph using the Adjacency Matrix. Generally, the Adjacency matrix is used to check if there is any edge available between two vertices or not. In the Adjacency matrix, we take a 2D array of size v*V, where V is the number of vertices in a graph and array[i][j] = 1 indicates that there is an edge between vertex i and j. The following example explains the Adjacency matrix of a graph: Graph Representation using Adjacency Matrix Java Program We have given the number of vertices 'v' and edges 'E' of a bidirectional graph. Our task is to build a graph through the adjacency matrix and print it. Example 1: Input: 5 7 0 1 0 4 1 2 1 3 1 4 2 3 3 4 Output: 0 1 0 0 1  1 0 1 1 1  0 1 0 1 0  0 1 1 0 1  1 1 0 1 0  Java Code: import java.util....
Read more

Java Method Overloading - The Coding Shala

Image
Home >> Learn Java >> Java Method Overloading Java Method Overloading Java class can have more than one method with the same name but different in parameters, known as Method Overloading. Question: What is the use of method overloading? Answer:  Suppose we want to perform some operation like an addition but addition can be performed between two numbers, three numbers or two floats or more. So instead of using different methods, we use the same name of the method with different parameters. This can increase the readability of the program. Method overloading can be achieved by changing numbers of arguments or by changing the data types. Example of Method Overloading in Java The following example explains Method Overloading: //Method Overloading example class Addition { public int add ( int a , int b ){ return a + b ; } public int add ( int a , int b , int c ){ return a + b + c ; ...
Read more

Client-Server Java Program (Socket Programming) - The Coding Shala

Home >> Computer Network >> Client-Server Java Program Client-Server Java Program (Socket Programming) Java Program to Send a Message from Client to Server and receive a Response back using socket programming. The first step is to run the Server.java program. Then Run Client.java program and enter the IP address and port address of the server into the Client program. Java Code of Server.Java:  import java.io. * ; import java.net.ServerSocket; import java.net.Socket; public class Server { private static Socket socket; public static void main (String[] args) { try { int port = 25000 ; ServerSocket serverSocket = new ServerSocket(port); System.out.println( "Server Started and listening to the port 25000" ); //Server is running always. This is done using this while(true) loop while ( true ) { //Reading the message ...
Read more