圖論 - 圖的深度優先遍歷c++實現

圖的深度優先遍歷c++實現

• 深度優先搜索

---

鄰接矩陣的創建

	int i, j, m, a, b;
	cin >> n >> m;
	//初始化二維矩陣
	for (i = 1; i <= n; i++)
		for (j = 1; j <= n; j++)
			if (i == j)e[i][j] = 0;
			else e[i][j] = 0x3f;

	//讀入頂點之間的邊
	for (i = 1; i <= m; i++)
	{
		cin >> a >> b;
		e[a][b] = 1;
		e[b][a] = 1; //無向圖需要將其對應的點的左邊也賦值為1
	}

---

深度優先搜索算法實現

void dfs(int cur)
{
	int i;
	cout << cur << " ";
	sum++;//每訪問一個節點sum就++
	if (sum == n)return;//所有的頂點已經訪問過直接退出
	for (int i = 1; i <= n; i++)
	{
		//判斷當前頂點cur到頂點i是否有邊,並判斷頂點i是否已經訪問過
		if (e[cur][i] == 1 && book[i] == 0)
		{
			book[i] = 1;
			dfs(i);
		}
	}
	return;
}

---

整體代碼

#include <iostream>
#include <cstdio>
using namespace std;
int book[101], sum, n, e[101][101];

void dfs(int cur)
{
	int i;
	cout << cur << " ";
	sum++;//沒訪問一個節點sum就++
	if (sum == n)return;//所有的頂點已經訪問過直接退出
	for (int i = 1; i <= n; i++)
	{
		//判斷當前頂點cur到頂點i是否有邊,並判斷頂點i是否已經訪問過
		if (e[cur][i] == 1 && book[i] == 0)
		{
			book[i] = 1;
			dfs(i);
		}
	}
	return;
}
int main()
{
	int i, j, m, a, b;
	cin >> n >> m;
	//初始化二維矩陣
	for (i = 1; i <= n; i++)
		for (j = 1; j <= n; j++)
			if (i == j)e[i][j] = 0;
			else e[i][j] = 0x3f;

	//讀入頂點之間的邊
	for (i = 1; i <= m; i++)
	{
		cin >> a >> b;
		e[a][b] = 1;
		e[b][a] = 1; //無向圖需要將其對應的點的左邊也賦值為1
	}

	//從頂點1出發
	book[1] = 1;//標記一號頂點已經被訪問
	dfs(1);//從1號頂點開始遍歷
	system("pause");
	return 0;
}