拓扑排序模板

#include <stdio.h>#include <string.h>#include <iostream>#include <algorithm>#include <queue>using namespace std;const int maxn = 20010;//ip表示第几条边//indeg表示入度int head[maxn], ip, indeg[maxn];int n, m, seq[maxn];//seg表示要干的事struct note{    int v,next;} edge[maxn];void Init(){    memset(head, -1, sizeof(head));    memset(indeg, 0, sizeof(indeg));    ip = 0;}void addedge(int u, int v)//增加边，u是初始点，v是终点{    edge[ip].v = v;    edge[ip].next = head[u];    head[u] = ip++;}int topo()//拓扑排序{    queue<int> q;    for(int i=1; i<=n; i++)        if(indeg[i] == 0)            q.push(i);    int k = 0;    bool res = false;    while(!q.empty())    {        if(q.size() != 1)            res = true;        int u = q.front();        q.pop();        k++;        for(int i=head[u]; i!=-1; i=edge[i].next)        {            int v = edge[i].v;            indeg[v]--;            if(indeg[v] == 0)            {                //seq[v] = seq[u]+1;                q.push(v);            }        }    }    if(k < n) return -1;//No    if(res) return 0;//Only    return 1;//正常}