C++实现Bellman-Ford算法（长度+路径）

 Bellman-Ford算法适用于不含负环路的图，比Dijkstra适用范围广。但是时间复杂度为O(n^3)。

#include 
#include 
#include 
using namespace std;
#define N = 1000
stack Q;
int path[N];
int dist[N][N];
int A[N][N];
void show_path(int k);

int main()
{
	int ppath[N];
	int n, t, min, front, node;
	t = 0;
	cout << "Please enter the number of vertex in your graph:";
	cout << endl;
	cin >> n;
	cout << "Please enter your graph as a matrix:";
	cout << endl;
	for (int i = 1; i <= n; i++)
		for (int j = 1; j <= n; j++)
			cin >> A[i][j];
	path[1] = 0; dist[1][0] = 0;
	for (int i = 2; i <= n; i++)
		for (int j = 0; j <= n; j++)
			dist[i][j] = 1000000;
	
	while (t < n)
	{
		for (int i = 2; i <= n; i++)
		{
			min = dist[1][t]+A[1][i]; front = 1;
			for (int j = 2; j <= n; j++)
			{
				if (min > dist[j][t] + A[j][i])
				{
					min = dist[j][t] + A[j][i];
					front = j;
				}
			}
			dist[i][t+1] = min;
			if (min < dist[i][t])
				path[i] = front;
		}
		t++;
	}
	//cout << path[1] << endl;
	for (int i = 1; i <= n; i++)
	{
		cout << "node" << i << "; " << dist[i][n] << endl;
		show_path(i);
	}

	system("pause");
	return 0;
}


void show_path(int k)
{
	int h = k;
	//stack Q;
	while (!Q.empty())
		Q.pop();
	while (h)
	{
		Q.push(h);
		h = path[h];
	}
	while (!Q.empty())
	{
		cout << Q.top() << " ";
		Q.pop();
	}
	cout << endl;

	return;
}