AcWing 1191. 家谱树

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拓扑排序祼题模板

#include <bits/stdc++.h>
using namespace std;

const int N = 110, M = N * N;

int n;
int q[N];
int d[N];
int h[N], e[M], ne[M], idx;
void add(int a, int b) {
    e[idx] = b, ne[idx] = h[a], h[a] = idx++;
}

void topsort() {
    int hh = 0, tt = -1;
    //所有入度为0的入队列
    for (int i = 1; i <= n; i++)
        if (!d[i])
            q[++tt] = i;

    while (hh <= tt) {
        int t = q[hh++];
        for (int i = h[t]; ~i; i = ne[i]) {
            int j = e[i];
            if (--d[j] == 0)
                q[++tt] = j;
        }
    }
}

int main() {
    memset(h, -1, sizeof h);
    cin >> n;
    for (int i = 1; i <= n; i++) {
        int son;
        while (cin >> son, son) {
            add(i, son);
            d[son]++; //入度++
        }
    }
    //拓扑序
    topsort();
    //输出任意一组拓扑序,q数组中就记录的拓扑序
    for (int i = 0; i < n; i++) printf("%d ", q[i]);
    return 0;
}