在图中查找特定顶点的度数
给定一个图 G(V,E) 作为邻接矩阵表示和一个顶点，求图中顶点 v 的度数。
例子 ：
0-----1
|\ |
| \ |
| \|
2-----3
Input : ver = 0
Output : 3
Input : ver = 1
Output : 2算法：-
1. Create the graphs adjacency matrix from src to des
2. For the given vertex then check if
a path from this vertices to other exists then
increment the degree.
3. Return degree 下面是该方法的实现。
C++
// CPP program to find degree of a vertex.
#include
using namespace std;
// structure of a graph
struct graph
{
// vertices
int v;
// edges
int e;
// direction from src to des
int **dir;
};
// Returns degree of ver in given graph
int findDegree(struct graph *G, int ver)
{
// Traverse through row of ver and count
// all connected cells (with value 1)
int degree = 0;
for (int i=0; iv; i++)
// if src to des is 1 the degree count
if (G-> dir[ver][i] == 1)
degree++;
// below line is to account for self loop in graph
// check sum of degrees in graph theorem
if(G-> dir[ver][ver] == 1)
degree++;
return degree;
}
struct graph *createGraph(int v,int e)
{
// G is a pointer of a graph
struct graph *G = new graph;
G->v = v;
G->e = e;
// allocate memory
G->dir = new int*[v];
for (int i = 0;i < v;i++)
G->dir[i] = new int[v];
/* 0-----1
| \ |
| \ |
| \ |
2-----3 */
//direction from 0
G->dir[0][1]=1;
G->dir[0][2]=1;
G->dir[0][3]=1;
//direction from 1
G->dir[1][0]=1;
G->dir[1][3]=1;
//direction from 2
G->dir[2][0]=1;
G->dir[2][3]=1;
//direction from 3
G->dir[3][0]=1;
G->dir[3][1]=1;
G->dir[3][2]=1;
return G;
}
// Driver code
int main()
{
int vertices = 4;
int edges = 5;
struct graph *G = createGraph(vertices, edges);
// loc is find the degree of
// particular vertex
int ver = 0;
int degree = findDegree(G, ver);
cout << degree << "\n";
return 0;
} Java
// Java program to find degree of a vertex.
class DegreeOfVertex
{
//Structure of Graph
static class Graph
{
// vertices and edges
int v, e;
int[][] dir;
//Graph Constructor
Graph(int v, int e) {
this.v = v;
this.e = e;
dir = new int[v][];
for (int i = 0; i < v; i++)
dir[i] = new int[v];
}
}
static Graph createGraph(int v, int e)
{
Graph G = new Graph(v, e);
/* 0-----1
| \ |
| \ |
| \ |
2-----3 */
//direction from 0
G.dir[0][1] = 1;
G.dir[0][2] = 1;
G.dir[0][3] = 1;
//direction from 1
G.dir[1][0] = 1;
G.dir[1][3] = 1;
//direction from 2
G.dir[2][0] = 1;
G.dir[2][3] = 1;
//direction from 3
G.dir[3][0] = 1;
G.dir[3][1] = 1;
G.dir[3][2] = 1;
return G;
}
static int findDegree(Graph G, int ver)
{
int degree = 0;
for (int i = 0; i < G.v; i++) {
if (G.dir[ver][i] == 1)
degree++;
}
// below line is to account for self loop in graph
// check sum of degrees in graph theorem
if(G.dir[ver][ver] == 1) degree++;
return degree;
}
// Driver code
public static void main(String[] args)
{
int vertices = 4;
int edges = 5;
// Creating a Graph
Graph G = createGraph(vertices, edges);
int ver = 0;
// Function calling
int degree = findDegree(G, ver);
System.out.println(degree);
}
}Python3
# Python3 program to find degree of a vertex.
# Structure of Graph
class Graph:
# vertices and edges
v = None
e = None
diri = []
# Graph Constructor
def __init__(self, v, e):
self.v = v
self.e = e
self.diri = [[0 for i in range(v)]
for j in range(v)]
def createGraph(v, e):
G = Graph(v, e)
# /* 0-----1
# | \ |
# | \ |
# | \ |
# 2-----3 */
# direction from 0
G.diri[0][1] = 1
G.diri[0][2] = 1
G.diri[0][3] = 1
# direction from 1
G.diri[1][0] = 1
G.diri[1][3] = 1
# direction from 2
G.diri[2][0] = 1
G.diri[2][3] = 1
# direction from 3
G.diri[3][0] = 1
G.diri[3][1] = 1
G.diri[3][2] = 1
return G
def findDegree(G, ver):
degree = 0
for i in range(G.v):
if G.diri[ver][i] == 1:
degree += 1
if G.diri[ver][ver] == 1:
degree += 1
return degree
# Driver Code
if __name__ == "__main__":
vertices = 4
edges = 5
# Creating a Graph
G = createGraph(vertices, edges)
ver = 0
# Function calling
degree = findDegree(G, ver)
print(degree)
# This code is contributed by
# sanjeev2552C#
// C# program to find degree of a vertex.
using System;
class GFG
{
// Structure of Graph
public class Graph
{
// vertices and edges
public int v, e;
public int[,] dir;
//Graph Constructor
public Graph(int v, int e)
{
this.v = v;
this.e = e;
dir = new int[v,v];
}
}
static Graph createGraph(int v, int e)
{
Graph G = new Graph(v, e);
/* 0-----1
| \ |
| \ |
| \ |
2-----3 */
// direction from 0
G.dir[0, 1] = 1;
G.dir[0, 2] = 1;
G.dir[0, 3] = 1;
// direction from 1
G.dir[1, 0] = 1;
G.dir[1, 3] = 1;
// direction from 2
G.dir[2, 0] = 1;
G.dir[2, 3] = 1;
//direction from 3
G.dir[3, 0] = 1;
G.dir[3, 1] = 1;
G.dir[3, 2] = 1;
return G;
}
static int findDegree(Graph G, int ver)
{
int degree = 0;
for (int i = 0; i < G.v; i++)
{
if (G.dir[ver,i] == 1)
degree++;
}
return degree;
}
// Driver code
public static void Main(String[] args)
{
int vertices = 4;
int edges = 5;
// Creating a Graph
Graph G = createGraph(vertices, edges);
int ver = 0;
// Function calling
int degree = findDegree(G, ver);
Console.WriteLine(degree);
}
}
// This code is contributed by 29AjayKumarJavascript
输出
3