打印有向图的邻接表
邻接表用于表示图形。这里，对于图中的每个顶点，我们有一个列表，列出了特定顶点有一条边的所有其他顶点。
问题:给定邻接表和图的顶点数和边数，任务是表示有向图的邻接表。
示例:
输入: V = 3，边[][]= {{0，1}，{1，2} {2，0}}
输出:0->1 1->2 2->0 T5】解释: 输出表示给定图形的邻接表。
输入: V = 4，边[][] = {{0，1}，{1，2}，{1，3}，{2，3}，{3，0}}
输出:0->1 1->2 3 2->3 3->0 解释: 输出表示给定图形的邻接表。
方法(使用*):*主要思想是将图表示为向量阵列，使得每个向量表示单个顶点的邻接表。使用 STL，代码变得更简单，更容易理解。
下面是上述方法的实现:
C++
// C++ program for the above approach
#include <bits/stdc++.h>
using namespace std;
// Function to add edges
void addEdge(vector<int> adj[], int u, int v)
{
adj[u].push_back(v);
}
// Function to print adjacency list
void adjacencylist(vector<int> adj[], int V)
{
for (int i = 0; i < V; i++) {
cout << i << "->";
for (int& x : adj[i]) {
cout << x << " ";
}
cout << endl;
}
}
// Function to initialize the adjacency list
// of the given graph
void initGraph(int V, int edges[3][2], int noOfEdges)
{
// To represent graph as adjacency list
vector<int> adj[V];
// Traverse edges array and make edges
for (int i = 0; i < noOfEdges; i++) {
// Function call to make an edge
addEdge(adj, edges[i][0], edges[i][1]);
}
// Function Call to print adjacency list
adjacencylist(adj, V);
}
// Driver Code
int main()
{
// Given vertices
int V = 3;
// Given edges
int edges[3][2] = { { 0, 1 }, { 1, 2 }, { 2, 0 } };
int noOfEdges = 3;
// Function Call
initGraph(V, edges, noOfEdges);
return 0;
}
Java 语言(一种计算机语言，尤用于创建网站)
// Java program for the above approach
import java.util.*;
class GFG
{
// Function to add edges
static void addEdge(Vector<Integer> adj[], int u, int v)
{
adj[u].add(v);
}
// Function to print adjacency list
static void adjacencylist(Vector<Integer> adj[], int V)
{
for (int i = 0; i < V; i++) {
System.out.print(i+ "->");
for (int x : adj[i]) {
System.out.print(x+ " ");
}
System.out.println();
}
}
// Function to initialize the adjacency list
// of the given graph
static void initGraph(int V, int edges[][], int noOfEdges)
{
// To represent graph as adjacency list
@SuppressWarnings("unchecked")
Vector<Integer> adj[] = new Vector[3];
for(int i =0;i<adj.length;i++) {
adj[i] = new Vector<>();
}
// Traverse edges array and make edges
for (int i = 0; i < noOfEdges; i++) {
// Function call to make an edge
addEdge(adj, edges[i][0], edges[i][1]);
}
// Function Call to print adjacency list
adjacencylist(adj, V);
}
// Driver Code
public static void main(String[] args)
{
// Given vertices
int V = 3;
// Given edges
int edges[][] = { { 0, 1 }, { 1, 2 }, { 2, 0 } };
int noOfEdges = 3;
// Function Call
initGraph(V, edges, noOfEdges);
}
}
// This code is contributed by gauravrajput1
Python 3
# Python program for the above approach
# Function to add edges
def addEdge(adj, u, v):
adj[u].append(v)
# Function to print adjacency list
def adjacencylist(adj, V):
for i in range (0, V):
print(i, "->", end="")
for x in adj[i]:
print(x , " ", end="")
print()
# Function to initialize the adjacency list
# of the given graph
def initGraph(V, edges, noOfEdges):
adj = [0]* 3
for i in range(0, len(adj)):
adj[i] = []
# Traverse edges array and make edges
for i in range(0, noOfEdges) :
# Function call to make an edge
addEdge(adj, edges[i][0], edges[i][1])
# Function Call to print adjacency list
adjacencylist(adj, V)
# Driver Code
# Given vertices
V = 3
# Given edges
edges = [[0, 1 ], [1, 2 ], [2, 0 ]]
noOfEdges = 3;
# Function Call
initGraph(V, edges, noOfEdges)
# This code is contributed by AR_Gaurav
C#
// C# program for the above approach
using System;
using System.Collections.Generic;
public class GFG
{
// Function to add edges
static void addEdge(List<int> []adj, int u, int v)
{
adj[u].Add(v);
}
// Function to print adjacency list
static void adjacencylist(List<int> []adj, int V)
{
for (int i = 0; i < V; i++) {
Console.Write(i+ "->");
foreach (int x in adj[i]) {
Console.Write(x+ " ");
}
Console.WriteLine();
}
}
// Function to initialize the adjacency list
// of the given graph
static void initGraph(int V, int [,]edges, int noOfEdges)
{
// To represent graph as adjacency list
List<int> []adj = new List<int>[3];
for(int i = 0; i < adj.Length; i++) {
adj[i] = new List<int>();
}
// Traverse edges array and make edges
for (int i = 0; i < noOfEdges; i++) {
// Function call to make an edge
addEdge(adj, edges[i,0], edges[i,1]);
}
// Function Call to print adjacency list
adjacencylist(adj, V);
}
// Driver Code
public static void Main(String[] args)
{
// Given vertices
int V = 3;
// Given edges
int [,]edges = { { 0, 1 }, { 1, 2 }, { 2, 0 } };
int noOfEdges = 3;
// Function Call
initGraph(V, edges, noOfEdges);
}
}
// This code is contributed by Amit Katiyar
**Output:
0->1
1->2
2->0**
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