oj.uz

Submission #672022

# Submission time Handle Problem Language Result Execution time Memory
672022 2022-12-14T15:52:45 Z LittleCube Alternating Current (BOI18_alternating) C++14
0 / 100
 73 ms 11468 KB 
#include <bits/stdc++.h>
#define ll long long
#define pii pair<int, int>
#define pll pair<ll, ll>
#define F first
#define S second
using namespace std;

int N, M, ans[100005], a[100005], b[100005];
vector<int> E[100005];

struct segTree
{
    int seg[400005], lazy[400005];

    int getval(int i)
    {
        return seg[i] + lazy[i];
    }

    void push(int i)
    {
        lazy[i << 1] += lazy[i];
        lazy[i << 1 | 1] += lazy[i];
        lazy[i] = 0;
    }

    void pull(int i)
    {
        seg[i] = min(getval(i << 1), getval(i << 1 | 1));
    }

    void modify(int mL, int mR, int val, int i = 1, int L = 1, int R = N)
    {
        if (mL <= L && R <= mR)
            lazy[i] += val;
        else if (R < mL || mR < L)
            return;
        else
        {
            int mid = (L + R) / 2;
            push(i);
            modify(mL, mR, val, i << 1, L, mid);
            modify(mL, mR, val, i << 1 | 1, mid + 1, R);
            pull(i);
        }
    }

    int query(int qL, int qR, int i = 1, int L = 1, int R = N)
    {
        if (qL <= L && R <= qR)
            return getval(i);
        else if (R < qL || qR < L)
            return 1e9;
        else
        {
            int mid = (L + R) / 2;
            push(i);
            pull(i);
            return min(query(qL, qR, i << 1, L, mid), query(qL, qR, i << 1 | 1, mid + 1, R));
        }
    }
} seg;

bool dfs(int u)
{
    bool r = 1;
    for (int v : E[u])
        if (ans[v] == 0)
        {
            ans[v] = ans[u] ^ 3;
            r &= dfs(v);
        }
        else
            r &= (ans[u] ^ ans[v]) == 3;
    return r;
}

signed main()
{
    ios::sync_with_stdio(0), cin.tie(0);
    cin >> N >> M;
    set<int> sweep;
    vector<pii> event;
    for (int i = 1; i <= M; i++)
    {
        cin >> a[i] >> b[i];
        if (b[i] < a[i])
        {
            sweep.insert(i);
            event.emplace_back(pii(b[i] + 1, -i));
            event.emplace_back(pii(a[i], i));
        }
        else
        {
            event.emplace_back(pii(a[i], i));
            event.emplace_back(pii(b[i] + 1, -i));
        }
    }
    sort(event.begin(), event.end());
    for (int i = 1, j = 0; i <= N; i++)
    {
        while (j < event.size() && event[j].F == i)
        {
            auto [t, k] = event[j];
            if (k > 0)
                sweep.insert(k);
            else
                sweep.erase(-k);
            j++;
        }
        if (sweep.size() == 1)
        {
            cout << "impossible\n";
            return 0;
        }
        else if (sweep.size() == 2)
        {
            int u = *sweep.begin(), v = *next(sweep.begin());
            E[u].emplace_back(v);
            E[v].emplace_back(u);
        }
    }
    for (int i = 1; i <= M; i++)
        if (ans[i] == 0 && !E[i].empty())
        {
            ans[i] = 1;
            if (!dfs(i))
            {
                cout << "impossible\n";
                return 0;
            }
        }
    for (int i = 1; i <= M; i++)
        if (ans[i] <= 1)
        {
            if (b[i] < a[i])
            {
                seg.modify(a[i], N, 1);
                seg.modify(1, b[i], 1);
            }
            else
                seg.modify(a[i], b[i], 1);
        }
    
    for (int i = 1; i <= M; i++)
        if (ans[i] == 0)
        {
            int rem;
            if (b[i] < a[i])
                rem = min(seg.query(a[i], N), seg.query(1, b[i]));
            else
                rem = seg.query(a[i], b[i]);

            if (rem >= 2)
            {
                ans[i] = 2;
                if (b[i] < a[i])
                {
                    seg.modify(a[i], N, -1);
                    seg.modify(1, b[i], -1);
                }
                else
                    seg.modify(a[i], b[i], -1);
            }
            else
                ans[i] = 1;
        }
    for (int i = 1; i <= M; i++)
        cout << ans[i] - 1;
    cout << '\n';
}
/*
5 6
1 3
2 4
3 5
4 1
5 2
1 3
*/

Compilation message

alternating.cpp: In function 'int main()':
alternating.cpp:103:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  103 |         while (j < event.size() && event[j].F == i)
      |                ~~^~~~~~~~~~~~~~
alternating.cpp:105:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  105 |             auto [t, k] = event[j];
      |                  ^

Subtask #1
0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Correct 2 ms 2644 KB Output is correct
19 Correct 2 ms 2684 KB Output is correct
20 Correct 1 ms 2680 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 1 ms 2644 KB Output is correct
24 Correct 1 ms 2680 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Incorrect 2 ms 2680 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Correct 2 ms 2644 KB Output is correct
19 Correct 2 ms 2684 KB Output is correct
20 Correct 1 ms 2680 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 1 ms 2644 KB Output is correct
24 Correct 1 ms 2680 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Incorrect 2 ms 2680 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Correct 2 ms 2644 KB Output is correct
19 Correct 2 ms 2684 KB Output is correct
20 Correct 1 ms 2680 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 1 ms 2644 KB Output is correct
24 Correct 1 ms 2680 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Incorrect 2 ms 2680 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# Verdict Execution time Memory Grader output
1 Correct 48 ms 10108 KB Output is correct
2 Correct 3 ms 3664 KB Output is correct
3 Correct 16 ms 4092 KB Output is correct
4 Correct 72 ms 7888 KB Output is correct
5 Correct 68 ms 9988 KB Output is correct
6 Correct 36 ms 5352 KB Output is correct
7 Correct 68 ms 9852 KB Output is correct
8 Correct 6 ms 5076 KB Output is correct
9 Correct 5 ms 4836 KB Output is correct
10 Correct 73 ms 11468 KB Output is correct
11 Correct 55 ms 9812 KB Output is correct
12 Correct 71 ms 10924 KB Output is correct
13 Incorrect 3 ms 3840 KB no wires in direction 0 between segments 100000 and 100000
14 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 2644 KB Output is correct
2 Correct 1 ms 2644 KB Output is correct
3 Correct 2 ms 2644 KB Output is correct
4 Correct 2 ms 2644 KB Output is correct
5 Correct 2 ms 2644 KB Output is correct
6 Correct 2 ms 2644 KB Output is correct
7 Correct 1 ms 2644 KB Output is correct
8 Correct 1 ms 2644 KB Output is correct
9 Correct 1 ms 2644 KB Output is correct
10 Correct 1 ms 2644 KB Output is correct
11 Correct 1 ms 2644 KB Output is correct
12 Correct 1 ms 2644 KB Output is correct
13 Correct 2 ms 2644 KB Output is correct
14 Correct 2 ms 2644 KB Output is correct
15 Correct 1 ms 2644 KB Output is correct
16 Correct 2 ms 2644 KB Output is correct
17 Correct 1 ms 2644 KB Output is correct
18 Correct 2 ms 2644 KB Output is correct
19 Correct 2 ms 2684 KB Output is correct
20 Correct 1 ms 2680 KB Output is correct
21 Correct 2 ms 2644 KB Output is correct
22 Correct 2 ms 2644 KB Output is correct
23 Correct 1 ms 2644 KB Output is correct
24 Correct 1 ms 2680 KB Output is correct
25 Correct 2 ms 2644 KB Output is correct
26 Correct 2 ms 2644 KB Output is correct
27 Incorrect 2 ms 2680 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -