oj.uz

Submission #53895

# Submission time Handle Problem Language Result Execution time Memory
53895 2018-07-01T15:13:36 Z paulica Potemkin cycle (CEOI15_indcyc) C++14
90 / 100
 75 ms 3900 KB 
#include <bits/stdc++.h>
using namespace std;

#define _ << " _ " <<
#define TRACE(x) cout << #x << " = " << x << endl

#define fi first
#define se second
typedef pair<int, int> pii;

const int MaxN = 1010, MaxR = 1e5 + 10;
int n, r;

vector<pii> e[MaxN];
bool con[MaxN][MaxN];

pii edg[MaxR];
bool vis[MaxR], stk[MaxR];

//int pre[MaxR];
stack<int> path;

void dfs(int x, int y, int id) {
    vis[id] = true;
    stk[id] = true;
    path.push(y);

    for (pii z : e[y]) {
        if (!con[x][z.fi] && z.fi != x) {
            if (!vis[z.se]) {
                //pre[z.se] = id;
                dfs(y, z.fi, z.se);
            } else if (stk[z.se]) {
                //vector<int> cyc = {y};
                //for (int u = id; cyc.size() == 1 || cyc.back() != y; u = pre[u])
                //    cyc.push_back(edg[u].fi + edg[u].se - cyc.back());
                //cyc.pop_back();
                //for (int i : path) TRACE(i);
                vector<int> cyc = {path.top()};
                for (path.pop(); path.top() != cyc[0]; path.pop())
                    cyc.push_back(path.top());
                //for (int i : cyc) TRACE(i);
                
                int m = cyc.size();
                for (int len = 3; len < m; len++)
                    for (int i = 0; i < m; i++) {
                        if (con[cyc[i]][cyc[(i + len) % m]]) {
                            for (int j = (i + 1) % m; j != i; j = (j + 1) % m)
                                cout << cyc[j] << " ";
                            cout << cyc[i];

                            exit(0);                
                        }
                    }
            }
        }
    }

    stk[id] = false;
    path.pop();
}

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(0);

    cin >> n >> r;
    
    for (int i = 0; i < r; i++) {
        int x, y;
        cin >> x >> y;
        
        e[x].push_back({y, i});
        e[y].push_back({x, i});

        con[x][y] = con[y][x] = true;

        edg[i] = {x, y};
    }

    for (int i = 0; i < r; i++) {
        if (!vis[i]) {
            path.push(edg[i].fi);
            dfs(edg[i].fi, edg[i].se, i);
            path.pop();
        }
    }

    cout << "no";

    return 0;
}

Subtask #1
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 376 KB Output is correct
2 Correct 2 ms 376 KB Output is correct
3 Correct 2 ms 412 KB Output is correct
4 Correct 2 ms 428 KB Output is correct
5 Correct 2 ms 428 KB Output is correct

Subtask #2
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 488 KB Output is correct

Subtask #3
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 520 KB Output is correct
2 Correct 2 ms 520 KB Output is correct

Subtask #4
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 664 KB Output is correct

Subtask #5
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 2 ms 664 KB Output is correct
2 Correct 2 ms 664 KB Output is correct

Subtask #6
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 920 KB Output is correct
2 Correct 3 ms 920 KB Output is correct
3 Correct 4 ms 1176 KB Output is correct
4 Correct 4 ms 1176 KB Output is correct

Subtask #7
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 1176 KB Output is correct
2 Correct 3 ms 1176 KB Output is correct

Subtask #8
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 25 ms 3048 KB Output is correct
2 Incorrect 10 ms 3048 KB Repeated vertex
3 Halted 0 ms 0 KB -

Subtask #9
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 3048 KB Output is correct
2 Correct 11 ms 3048 KB Output is correct

Subtask #10
10.0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 31 ms 3824 KB Output is correct
2 Correct 75 ms 3900 KB Output is correct
3 Correct 20 ms 3900 KB Output is correct
4 Correct 33 ms 3900 KB Output is correct