Program to find total number of edges in a Complete Graph

Last Updated : 02 Sep, 2022

Given N number of vertices of a Graph. The task is to find the total number of edges possible in a complete graph of N vertices.
Complete Graph: A Complete Graph is a graph in which every pair of vertices is connected by an edge.

Examples:

Input : N = 3 Output : Edges = 3  Input : N = 5 Output : Edges = 10

The total number of possible edges in a complete graph of N vertices can be given as,

Total number of edges in a complete graph of N vertices = ( n * ( n - 1 ) ) / 2

Example 1: Below is a complete graph with N = 5 vertices.

The total number of edges in the above complete graph = 10 = (5)*(5-1)/2.

Implementation:

C++

// C++ implementation to find the // number of edges in a complete graph  #include <bits/stdc++.h> using namespace std;  // Function to find the total number of // edges in a complete graph with N vertices int totEdge(int n) {     int result = 0;      result = (n * (n - 1)) / 2;      return result; }  // Driver Code int main() {     int n = 6;      cout << totEdge(n);      return 0; }

Java

// Java implementation to find the // number of edges in a complete graph  class GFG {      // Function to find the total number of // edges in a complete graph with N vertices static int totEdge(int n) {     int result = 0;      result = (n * (n - 1)) / 2;      return result; }      // Driver Code     public static void main(String []args)     {         int n = 6;         System.out.println(totEdge(n));     }  }

Python 3

# Python 3 implementation to   # find the number of edges  # in a complete graph   # Function to find the total  # number of edges in a complete # graph with N vertices def totEdge(n) :      result = (n * (n - 1)) // 2      return result              # Driver Code if __name__ == "__main__" :      n = 6      print(totEdge(n))  # This code is contributed # by ANKITRAI1

// C# implementation to find  // the number of edges in a // complete graph using System;  class GFG  {      // Function to find the total  // number of edges in a complete  // graph with N vertices static int totEdge(int n) {     int result = 0;      result = (n * (n - 1)) / 2;      return result; }  // Driver Code public static void Main() {     int n = 6;     Console.Write(totEdge(n)); } }  // This code is contributed  // by ChitraNayal

PHP

<?php // PHP implementation to find  // the number of edges in a  // complete graph   // Function to find the total  // number of edges in a complete // graph with N vertices  function totEdge($n)  {      $result = 0;       $result = ($n * ($n - 1)) / 2;       return $result;  }   // Driver Code  $n = 6;  echo totEdge($n);   // This code is contributed // by Shivi_Aggarwal ?>

JavaScript

<script>  // Javascript implementation to find the // number of edges in a complete graph  // Function to find the total number of // edges in a complete graph with N vertices function totEdge(n) {     var result = 0;      result = (n * (n - 1)) / 2;      return result; }  // Driver Code var n = 6; document.write( totEdge(n));  </script>

Output

Complexity Analysis:

Time Complexity: O(1)
Auxiliary Space: O(1)

Program to find total number of edges in a Complete Graph

Naman_Garg

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Program to find total number of edges in a Complete Graph

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