UVa 10305 Ordering Tasks

Description

拓扑排序

Algorithm

拓扑排序算法

Code

#include <cstdio>
#include <cstring>
#include <iostream>
using namespace std;
int n, m, t;
const int maxn = 100 + 9;
bool g[maxn][maxn];
int c[maxn], topo[maxn];
void dfs(int u)
{
  c[u] = -1;
  for (int v = 1; v <= n; v++)
    if (g[u][v] && !c[v]) dfs(v);
  c[u] = 1;
  topo[--t] = u;
}
void solve()
{
  memset(g, 0, sizeof(g));
  memset(c, 0, sizeof(c));
  memset(topo, 0, sizeof(topo));
  for (int i = 0; i < m; i++)
  {
    int x, y;
    cin >> x >> y;
    g[x][y] = true;
  }
  t = n;
  for (int u = 1; u <= n; u++)
    if (!c[u]) dfs(u);
  cout << topo[0];
  for (int i = 1; i < n; i++)
    cout << ' ' << topo[i];
  cout << endl;
}
int main()
{
// freopen("input.txt", "r", stdin);
  for (;;)
  {
    cin >> n >> m;
    if (n == 0 && m == 0) break;
    solve();
  }
}