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Submission #95871

# Submission time Handle Problem Language Result Execution time Memory
95871 2019-02-03T09:35:28 Z Kastanda Pipes (CEOI15_pipes) C++11
100 / 100
 3034 ms 5240 KB 
#include<bits/stdc++.h>
using namespace std;
const int N = 100005, M = N * 2;
int n, cnt, tk, H[N], Mn[N], stk[N], par[N];
int ts, head[N], nxt[M + M];
int m, from[M], to[M];
bitset < M > tree, bridge;
bitset < N > mark;
inline void AddEdge(int v, int u)
{
    from[ts >> 1] = v; to[ts >> 1] = u;
    nxt[ts] = head[v]; head[v] = ts;
    nxt[ts|1] = head[u]; head[u] = ts|1;
    ts += 2;
}
inline void DFS()
{
    int v, u;
    while (tk)
    {
        v = stk[tk];
        if (mark[v])
        {
            u = from[head[v] >> 1] ^ to[head[v] >> 1] ^ v;
            Mn[v] = min(Mn[v], Mn[u]);
            if (Mn[u] < H[u])
                bridge[head[v] >> 1] = 0;
            head[v] = nxt[head[v]];
        }
        if (!mark[v])
        {
            mark[v] = 1;
            Mn[v] = H[v];
        }
        for (; head[v] != -1; head[v] = nxt[head[v]])
            if ((head[v] >> 1) != par[tk])
            {
                u = from[head[v] >> 1] ^ to[head[v] >> 1] ^ v;
                if (mark[u])
                    Mn[v] = min(Mn[v], H[u]), bridge[head[v] >> 1] = 0;
                else
                {
                    H[u] = H[v] + 1;
                    tree[head[v] >> 1] = 1;

                    ++ tk;
                    stk[tk] = u;
                    par[tk] = head[v] >> 1;
                    break;
                }
            }
        if (head[v] == -1)
            tk --;
    }
}
inline void Unlaze()
{
    mark = 0; tree = 0;
    memset(H, 0, sizeof(H));
    for (int i = 1; i <= n; i++)
        if (!mark[i])
        {
            tk = 1;
            stk[tk] = i;
            par[tk] = -1;
            DFS();
        }
    cnt = 0;
    for (int i = 0; i < (ts >> 1); i++)
        if (tree[i])
        {
            bool a;
            a = tree[i];
            tree[i] = tree[cnt];
            tree[cnt] = a;

            a = bridge[i];
            bridge[i] = bridge[cnt];
            bridge[cnt] = a;

            swap(from[i], from[cnt]);
            swap(to[i], to[cnt]);
            cnt ++;
        }
    ts = 0;
    memset(nxt, -1, sizeof(nxt));
    memset(head, -1, sizeof(head));
    for (int i = 0; i < cnt; i++)
        AddEdge(from[i], to[i]);
}
int main()
{
    memset(nxt, -1, sizeof(nxt));
    memset(head, -1, sizeof(head));
    scanf("%d%d", &n, &m);
    for (int i = 1; i <= m; i++)
    {
        int v, u;
        scanf("%d%d", &v, &u);
        bridge[ts >> 1] = 1;
        AddEdge(v, u);
        if (ts >= M + M - 20)
            Unlaze();
    }
    Unlaze();
    for (int i = 0; i < (ts >> 1); i++)
        if (bridge[i])
            printf("%d %d\n", from[i], to[i]);
    return 0;
}

Compilation message

pipes.cpp: In function 'int main()':
pipes.cpp:95:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
     ~~~~~^~~~~~~~~~~~~~~~
pipes.cpp:99:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%d%d", &v, &u);
         ~~~~~^~~~~~~~~~~~~~~~

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 2816 KB Output is correct
2 Correct 4 ms 2816 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2816 KB Output is correct
2 Correct 6 ms 2816 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 163 ms 4292 KB Output is correct
2 Correct 163 ms 4360 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 269 ms 4344 KB Output is correct
2 Correct 314 ms 4396 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 447 ms 4564 KB Output is correct
2 Correct 376 ms 4612 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 716 ms 4956 KB Output is correct
2 Correct 597 ms 4680 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1214 ms 5084 KB Output is correct
2 Correct 1031 ms 4856 KB Output is correct

Subtask #8
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 1759 ms 5196 KB Output is correct
2 Correct 1793 ms 4856 KB Output is correct

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2390 ms 5212 KB Output is correct
2 Correct 2254 ms 4856 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3034 ms 5240 KB Output is correct
2 Correct 2299 ms 5048 KB Output is correct