拓扑排序bfs_dfs

dfs

#include <cstdio>
#include <cstring>
using namespace std;

const int maxn = 1e5+;
struct Edge{
    int lst;
    int to;
}edge[maxn*];
int head[maxn];

int qsz;

inline void add(int u, int v) {
    edge[qsz].lst = head[u];
    edge[qsz].to  = v;
    head[u] = qsz++;
}

int vis[maxn];
int  ans[maxn];
int qtot;
bool dfs(int u) {
    int v, i;
    vis[u] = -;
    for (i=head[u]; i; i=edge[i].lst) {
        v = edge[i].to;
        if (vis[v] == -) return false;
        else if (!vis[v] && !dfs(v)) return false;
    }
    ans[qtot--] = u;
    vis[u] = ;
    return true;
}

int main()
{
    int t, n, m, i, j, u, v;
    scanf("%d", &t);
    while (t--) {
        // init;
        qsz = ;
        memset(head, , sizeof(head));
        memset( vis, , sizeof( vis));
        scanf("%d%d", &n, &m);
        qtot = n;
        for (i=; i<=m; ++i) {
            scanf("%d%d", &u, &v);
            add(v, u);
        }
        for (i=; i<=n; ++i)
            if (!vis[i])
                if (!dfs(i))
                    break;

        if (!qtot) printf("Correct\n");
        else printf("Wrong\n");
    }

    return ;
}

bfs

#include <cstdio>
#include <cstring>
using namespace std;

const int maxn = 1e5+;
struct Edge{
    int lst;
    int to;
}edge[maxn*];
int head[maxn];
int qsz;

int inq[maxn];
int q[maxn];
int qhead;
inline void add(int u, int v) {
    edge[qsz].lst = head[u];
    edge[qsz].to  = v;
    head[u] = qsz++;
}

int main()
{
    int t, n, m, i, j, u, v;
    scanf("%d", &t);
    while (t--) {
        // init;
        qsz = ;
        memset(head, , sizeof(head));
        memset(inq,  , sizeof( inq));
        qhead = ;

        scanf("%d%d", &n, &m);
        for (i=; i<=m; ++i) {
            scanf("%d%d", &u, &v);
            add(u, v);
            inq[v]++;
        }
        for (i=; i<=n; ++i)
            if (!inq[i])
                q[qhead++] = i;
        for (i=; i<qhead; ++i) {
            for (j=head[q[i]]; j; j=edge[j].lst) {
                v = edge[j].to;
                inq[v]--;
                if (!inq[v]) q[qhead++] = v;
            }
        }
        if (qhead == n) printf("Correct\n");
        else printf("Wrong\n");
    }

    return ;
}