oj.uz

답안 #441518

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
441518 2021-07-05T09:49:39 Z abc864197532 Alternating Current (BOI18_alternating) C++17
0 / 100
 3000 ms 807064 KB 
#include <bits/stdc++.h>
using namespace std;
#define lli long long int
#define X first
#define Y second
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define pii pair<int, int>
#define all(x) x.begin(), x.end()
#define rall(x) x.rbegin(), x.rend()
#define test(args...) abc("[" + string(#args) + "]", args)
void abc() {cerr << endl;}
template <typename T, typename ...U> void abc(T a, U ...b) {
    cerr << a << ' ', abc(b...);
}
template <typename T> void printv(T l, T r) {
    while (l != r) cout << *l << " \n"[++l == r];
}
const int mod = 1e9 + 7, N = 100000;

int main () {
    srand(time(NULL));
    ios::sync_with_stdio(false);
    cin.tie(0);
    int n, m;
    cin >> n >> m;
    vector <pii> a(m);
    vector <int> seg[n];
    for (int i = 0, l, r; i < m; ++i) {
        cin >> a[i].X >> a[i].Y, --a[i].X;
        tie(l, r) = a[i];
        if (l < r) {
            for (int j = l; j < r; ++j) seg[j].pb(i);
        } else {
            for (int j = l; j < n; ++j) seg[j].pb(i);
            for (int j = 0; j < r; ++j) seg[j].pb(i);
        }
    }
    vector <vector <int>> adj(m);
    for (int i = 0; i < n; ++i) {
        if (seg[i].size() < 2) return cout << "impossible\n", 0;
        if (seg[i].size() == 2) adj[seg[i][0]].pb(seg[i][1]), adj[seg[i][1]].pb(seg[i][0]);
    }
    vector <int> ans(m, -1);
    bool odd_cycle = false;
    function<void(int)> dfs = [&](int v) {
        for (int u : adj[v]) {
            if (ans[u] == -1) {
                ans[u] = ans[v] ^ 1;
                dfs(u);
            } else if (ans[v] == ans[u]) {
                odd_cycle = true;
            }
        }
    };
    for (int i = 0; i < m; ++i) if (ans[i] == -1 && !adj[i].empty()) {
        ans[i] = 0;
        dfs(i);
    }
    if (odd_cycle) return cout << "impossible\n", 0;
    for (int i = 0; i < n; ++i) {
        int ok = 0;
        for (int j : seg[i]) {
            if (ans[j] == -1) continue;
            ok |= 1 << ans[j];
        }
        if (ok == 0) {
            ans[seg[i][0]] = 0;
            ans[seg[i][1]] = 1;
        } else if (ok != 3) {
            bool is = false;
            for (int j : seg[i]) {
                if (ans[j] == -1) continue;
                ans[j] = ok == 2 ? 0 : 1;
                is = true;
                break;
            }
            if (is) return cout << "impossible\n", 0;
        }
    }
    for (int i : ans) {
        cout << (i == -1 ? 0 : i);
    }
    cout << endl;
}

Subtask #1
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Incorrect 0 ms 204 KB 'impossible' claimed, but there is a solution
7 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Incorrect 0 ms 204 KB 'impossible' claimed, but there is a solution
7 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Incorrect 0 ms 204 KB 'impossible' claimed, but there is a solution
7 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Execution timed out 3144 ms 807064 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 1 ms 204 KB Output is correct
2 Correct 0 ms 204 KB Output is correct
3 Correct 1 ms 204 KB Output is correct
4 Correct 0 ms 212 KB Output is correct
5 Correct 0 ms 204 KB Output is correct
6 Incorrect 0 ms 204 KB 'impossible' claimed, but there is a solution
7 Halted 0 ms 0 KB -