poj 2367 Genealogical tree

裸的拓扑排序 图用邻接表表示

方法是dfs

#include<stdio.h>
#include<string.h>
const int MAXN = 1000;
struct edge{
    int u, v, next;
}e[MAXN];
int n;
int first[MAXN], cnt;
bool visit[MAXN], f;
int sort[MAXN], top;
void dfs(int s){
    if(visit[s])
        return;
    visit[s] = true;    
    for(int x = first[s]; x != -1; x = e[x].next){
        if(!visit[e[x].v])
            dfs(e[x].v);
    }
    sort[++top] = s;
}
void toposort(){
    memset(visit, false, sizeof(visit));
    top = -1;
    for(int i = 1; i <= n; ++i){
        if(!visit[i])
            dfs(i);
    }
}
int main(){
        scanf("%d",&n);
        memset(first, -1, sizeof(first));
    for(int i = 1, cnt = 0; i <= n; ++i){
        int a;
        while(true){
            scanf("%d",&a);
            if(!a)
                break;
            e[cnt].u = i;
            e[cnt].v = a;
            e[cnt].next = first[i];
            first[i] = cnt;
            cnt++;
        }
    }
    toposort();
    bool f = true;
    while(top != -1){
        if(f)
            f = false;
        else
            printf(" ");
        printf("%d",sort[top--]);
    }
    printf("\n");
    return 0;
}