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# Finding in and out degrees of all vertices in a graph

• Last Updated : 03 Sep, 2020

Given a directed graph, the task is to count the in and out degree of each vertex of the graph.
Examples:

```Input: Output:
Vertex    In    Out
0         1    2
1          2    1
2          2    3
3          2    2
4          2    2
5          2    2
6          2    1
```

Approach: Traverse adjacency list for every vertex, if size of the adjacency list of vertex i is x then the out degree for i = x and increment the in degree of every vertex that has an incoming edge from i. Repeat the steps for every vertex and print the in and out degrees for all the vertices in the end.

Below is the implementation of the above approach:

## C++

 `// C++ program to find the in and out degrees``// of the vertices of the given graph``#include ``using` `namespace` `std;`` ` `// Function to print the in and out degrees``// of all the vertices of the given graph``void` `findInOutDegree(list> adjlist,``                     ``int` `n)``{``    ``int``* iN = ``new` `int``[n]();``    ``int``* ouT = ``new` `int``[n]();`` ` `    ``list >::iterator nest_list;``    ``int` `i = 0;``     ` `    ``for``(nest_list = adjlist.begin(); ``        ``nest_list != adjlist.end();``        ``nest_list++) ``    ``{``        ``list<``int``> lst = *nest_list;`` ` `        ``// Out degree for ith vertex will be the count``        ``// of direct paths from i to other vertices``        ``ouT[i] = lst.size();``         ` `        ``for``(``auto` `it = lst.begin(); ``                 ``it != lst.end(); it++)``        ``{``            ``// Every vertex that has an incoming``            ``// edge from i``            ``iN[*it]++;``        ``}``        ``i++;``    ``}`` ` `    ``cout << ``"Vertex\t\tIn\t\tOut"` `<< endl;``    ``for``(``int` `k = 0; k < n; k++)``    ``{``        ``cout << k << ``"\t\t"``             ``<< iN[k] << ``"\t\t"` `             ``<< ouT[k] << endl;``    ``}``}`` ` `// Driver code``int` `main()``{``     ` `    ``// Adjacency list representation of the graph``    ``list> adjlist;`` ` `    ``// Vertices 1 and 2 have an incoming edge``    ``// from vertex 0``    ``list<``int``> tmp;``    ``tmp.push_back(1);``    ``tmp.push_back(2);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertex 3 has an incoming edge ``    ``// from vertex 1``    ``tmp.push_back(3);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertices 0, 5 and 6 have an incoming``    ``// edge from vertex 2``    ``tmp.push_back(0);``    ``tmp.push_back(5);``    ``tmp.push_back(6);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertices 1 and 4 have an incoming ``    ``// edge from vertex 3``    ``tmp.push_back(1);``    ``tmp.push_back(4);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertices 2 and 3 have an incoming ``    ``// edge from vertex 4``    ``tmp.push_back(2);``    ``tmp.push_back(3);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertices 4 and 6 have an incoming ``    ``// edge from vertex 5``    ``tmp.push_back(4);``    ``tmp.push_back(6);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``// Vertex 5 has an incoming ``    ``// edge from vertex 6``    ``tmp.push_back(5);``    ``adjlist.push_back(tmp);``    ``tmp.clear();`` ` `    ``int` `n = adjlist.size();``     ` `    ``findInOutDegree(adjlist, n);``}`` ` `// This code is contributed by saurabhgpta248    `

## Java

 `// Java program to find the in and out degrees``// of the vertices of the given graph``import` `java.util.*;`` ` `class` `GFG {`` ` `    ``// Function to print the in and out degrees``    ``// of all the vertices of the given graph``    ``static` `void` `findInOutDegree(List > adjList, ``int` `n)``    ``{``        ``int` `in[] = ``new` `int``[n];``        ``int` `out[] = ``new` `int``[n];`` ` `        ``for` `(``int` `i = ``0``; i < adjList.size(); i++) {`` ` `            ``List list = adjList.get(i);`` ` `            ``// Out degree for ith vertex will be the count``            ``// of direct paths from i to other vertices``            ``out[i] = list.size();``            ``for` `(``int` `j = ``0``; j < list.size(); j++)`` ` `                ``// Every vertex that has an incoming ``                ``// edge from i``                ``in[list.get(j)]++;``        ``}`` ` `        ``System.out.println(``"Vertex\tIn\tOut"``);``        ``for` `(``int` `k = ``0``; k < n; k++) {``            ``System.out.println(k + ``"\t"` `+ in[k] + ``"\t"` `+ out[k]);``        ``}``    ``}`` ` `    ``// Driver code``    ``public` `static` `void` `main(String args[])``    ``{``        ``// Adjacency list representation of the graph``        ``List > adjList = ``new` `ArrayList<>();`` ` `        ``// Vertices 1 and 2 have an incoming edge ``        ``// from vertex 0``        ``List tmp = ``           ``new` `ArrayList(Arrays.asList(``1``, ``2``));``        ``adjList.add(tmp);`` ` `        ``// Vertex 3 has an incoming edge from vertex 1``        ``tmp = ``new` `ArrayList(Arrays.asList(``3``));``        ``adjList.add(tmp);`` ` `        ``// Vertices 0, 5 and 6 have an incoming``        ``// edge from vertex 2``        ``tmp = ``          ``new` `ArrayList(Arrays.asList(``0``, ``5``, ``6``));``        ``adjList.add(tmp);`` ` `        ``// Vertices 1 and 4 have an incoming edge ``        ``// from vertex 3``        ``tmp = ``new` `ArrayList(Arrays.asList(``1``, ``4``));``        ``adjList.add(tmp);`` ` `        ``// Vertices 2 and 3 have an incoming edge``        ``// from vertex 4``        ``tmp = ``new` `ArrayList(Arrays.asList(``2``, ``3``));``        ``adjList.add(tmp);`` ` `        ``// Vertices 4 and 6 have an incoming edge``        ``// from vertex 5``        ``tmp = ``new` `ArrayList(Arrays.asList(``4``, ``6``));``        ``adjList.add(tmp);`` ` `        ``// Vertex 5 has an incoming edge from vertex 6``        ``tmp = ``new` `ArrayList(Arrays.asList(``5``));``        ``adjList.add(tmp);`` ` `        ``int` `n = adjList.size();``        ``findInOutDegree(adjList, n);``    ``}``}`

## Python3

 `# Python3 program to find the in and out ``# degrees of the vertices of the given graph `` ` `# Function to print the in and out degrees ``# of all the vertices of the given graph ``def` `findInOutDegree(adjList, n): ``     ` `    ``_in ``=` `[``0``] ``*` `n ``    ``out ``=` `[``0``] ``*` `n`` ` `    ``for` `i ``in` `range``(``0``, ``len``(adjList)): `` ` `        ``List` `=` `adjList[i] `` ` `        ``# Out degree for ith vertex will be the count ``        ``# of direct paths from i to other vertices ``        ``out[i] ``=` `len``(``List``) ``        ``for` `j ``in` `range``(``0``, ``len``(``List``)): `` ` `            ``# Every vertex that has ``            ``# an incoming edge from i ``            ``_in[``List``[j]] ``+``=` `1`` ` `    ``print``(``"Vertex\tIn\tOut"``) ``    ``for` `k ``in` `range``(``0``, n): ``        ``print``(``str``(k) ``+` `"\t"` `+` `str``(_in[k]) ``+` `                       ``"\t"` `+` `str``(out[k])) `` ` `# Driver code ``if` `__name__ ``=``=` `"__main__"``: ``     ` `    ``# Adjacency list representation of the graph ``    ``adjList ``=` `[] `` ` `    ``# Vertices 1 and 2 have an incoming edge ``    ``# from vertex 0 ``    ``adjList.append([``1``, ``2``]) `` ` `    ``# Vertex 3 has an incoming edge from vertex 1 ``    ``adjList.append([``3``]) `` ` `    ``# Vertices 0, 5 and 6 have an ``    ``# incoming edge from vertex 2 ``    ``adjList.append([``0``, ``5``, ``6``]) `` ` `    ``# Vertices 1 and 4 have an ``    ``# incoming edge from vertex 3 ``    ``adjList.append([``1``, ``4``]) `` ` `    ``# Vertices 2 and 3 have an ``    ``# incoming edge from vertex 4 ``    ``adjList.append([``2``, ``3``]) `` ` `    ``# Vertices 4 and 6 have an ``    ``# incoming edge from vertex 5 ``    ``adjList.append([``4``, ``6``]) `` ` `    ``# Vertex 5 has an incoming edge from vertex 6 ``    ``adjList.append([``5``]) `` ` `    ``n ``=` `len``(adjList) ``    ``findInOutDegree(adjList, n) ``     ` `# This code is contributed by Rituraj Jain`

## C#

 `// C# program to find the in and out degrees``// of the vertices of the given graph``using` `System;``using` `System.Collections.Generic;    `` ` `class` `GFG``{`` ` `// Function to print the in and out degrees``// of all the vertices of the given graph``static` `void` `findInOutDegree(List> adjList, ``int` `n)``{``    ``int` `[]iN = ``new` `int``[n];``    ``int` `[]ouT = ``new` `int``[n];`` ` `    ``for` `(``int` `i = 0; i < adjList.Count; i++) ``    ``{`` ` `        ``List<``int``> list = adjList[i];`` ` `        ``// Out degree for ith vertex will be the count``        ``// of direct paths from i to other vertices``        ``ouT[i] = list.Count;``        ``for` `(``int` `j = 0; j < list.Count; j++)`` ` `            ``// Every vertex that has an incoming ``            ``// edge from i``            ``iN[list[j]]++;``    ``}`` ` `    ``Console.WriteLine(``"Vertex\t\tIn\t\tOut"``);``    ``for` `(``int` `k = 0; k < n; k++)``    ``{``        ``Console.WriteLine(k + ``"\t\t"` `+ ``                      ``iN[k] + ``"\t\t"` `+ ouT[k]);``    ``}``}`` ` `// Driver code``public` `static` `void` `Main(String []args)``{``    ``// Adjacency list representation of the graph``    ``List > adjList = ``new` `List>();`` ` `    ``// Vertices 1 and 2 have an incoming edge ``    ``// from vertex 0``    ``List<``int``> tmp = ``    ``new` `List<``int``>{1, 2};``    ``adjList.Add(tmp);`` ` `    ``// Vertex 3 has an incoming edge from vertex 1``    ``tmp = ``new` `List<``int``>{3};``    ``adjList.Add(tmp);`` ` `    ``// Vertices 0, 5 and 6 have an incoming``    ``// edge from vertex 2``    ``tmp = ``    ``new` `List<``int``>{0, 5, 6};``    ``adjList.Add(tmp);`` ` `    ``// Vertices 1 and 4 have an incoming edge ``    ``// from vertex 3``    ``tmp = ``new` `List<``int``>{1, 4};``    ``adjList.Add(tmp);`` ` `    ``// Vertices 2 and 3 have an incoming edge``    ``// from vertex 4``    ``tmp = ``new` `List<``int``>{2, 3};``    ``adjList.Add(tmp);`` ` `    ``// Vertices 4 and 6 have an incoming edge``    ``// from vertex 5``    ``tmp = ``new` `List<``int``>{4, 6};``    ``adjList.Add(tmp);`` ` `    ``// Vertex 5 has an incoming edge from vertex 6``    ``tmp = ``new` `List<``int``>{5};``    ``adjList.Add(tmp);`` ` `    ``int` `n = adjList.Count;``    ``findInOutDegree(adjList, n);``}``}`` ` `// This code is contributed by 29AjayKumar`
Output:
```Vertex    In    Out
0    1    2
1    2    1
2    2    3
3    2    2
4    2    2
5    2    2
6    2    1
```

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