oj.uz

답안 #749619

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
749619 2023-05-28T10:07:57 Z anhduc2701 Alternating Current (BOI18_alternating) C++17
0 / 100
 133 ms 109644 KB 
/*
#pragma GCC optimize("Ofast")
#pragma GCC target("avx,avx2,fma")
#pragma GCC optimize("unroll-loops")
*/
#include <bits/stdc++.h>
using namespace std;
#define all(x) x.begin(), x.end()
#define len(x) ll(x.size())
#define eb emplace_back
#define PI acos(-1.0)
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define MIN(v) *min_element(all(v))
#define MAX(v) *max_element(all(v))
#define BIT(x, i) (1 & ((x) >> (i)))
#define MASK(x) (1LL << (x))
#define task "tnc"
#define rep(i, n) for (int i = 0; i < (n); i++)
#define rep1(i, n) for (int i = 1; i <= (n); i++)
typedef long long ll;
typedef long double ld;
const ll INF = 1e18;
const int maxn = 1e6 + 5;
const int mod = 1e9 + 7;
const int mo = 998244353;
using pi = pair<ll, ll>;
using vi = vector<ll>;
using pii = pair<pair<ll, ll>, ll>;
mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
struct seg
{
    int l, r, id;
    seg() {}
    seg(int _l, int _r, int _id)
    {
        l = _l;
        r = _r;
        id = _id;
    }
} A[maxn];
int pref[maxn];
vector<int> G[maxn];
int n, m;
int pref1[maxn];
vector<int> sus[maxn];
int col[maxn];
int ch = 0;
void dfs(int u)
{
    for (auto v : G[u])
    {
        if (col[v] == -1)
        {
            col[v] = col[u] ^ 1;
            dfs(v);
        }
        else if (col[v] != col[u] ^ 1)
        {
            ch = 1;
        }
    }
}
int pref2[maxn];
vector<pair<int, int>> st[maxn];
vector<int> era[maxn];
signed main()
{
    cin.tie(0), cout.tie(0)->sync_with_stdio(0);
    cin >> n >> m;
    for (int i = 1; i <= m; i++)
    {
        int l, r;
        cin >> l >> r;
        st[l].pb({r, i});
        pref[l]++;
        pref[r + 1]--;
        if (l > r)
            pref[1]++;
        A[i] = seg(l, r, i);
    }
    vector<int> check;
    for (int i = 1; i <= n; i++)
    {
        pref[i] += pref[i - 1];
        pref1[i] = pref1[i - 1];
        if (pref[i] == 2)
        {
            check.pb(i);
            pref1[i]++;
        }
        if (pref[i] == 1)
        {
            cout << "impossible\n";
            return 0;
        }
    }
    for (int i = 1; i <= n; i++)
    {
        if (A[i].l <= A[i].r)
        {
            if (pref1[A[i].r] - pref1[A[i].l - 1] > 0)
            {
                int v = lower_bound(check.begin(), check.end(), A[i].l) - check.begin();
                while (v < check.size() && check[v] <= A[i].r)
                {
                    sus[check[v]].pb(i);
                    v++;
                }
            }
        }
        else
        {
            int v = lower_bound(check.begin(), check.end(), A[i].l) - check.begin();
            while (v < check.size())
            {
                sus[check[v]].pb(i);
                v++;
            }
            v = lower_bound(check.begin(), check.end(), 1) - check.begin();
            while (v < check.size() && check[v] <= A[i].r)
            {
                sus[check[v]].pb(i);
                v++;
            }
        }
    }

    for (auto v : check)
    {
        G[sus[v][0]].pb(sus[v][1]);
        G[sus[v][1]].pb(sus[v][0]);
    }
    memset(col, -1, sizeof(col));
    for (int i = 1; i <= m; i++)
    {
        if (G[i].size() && col[i] == -1)
        {
            col[i] = 0;
            dfs(i);
        }
    }
    if (ch == 1)
    {
        cout << "impossible\n";
        return 0;
    }
    set<pair<int, int>> pq;
    for (int i = 1; i <= m; i++)
    {
        if (col[i] == 1)
        {
            pref2[A[i].l]++;
            pref2[A[i].r + 1]--;
            if (A[i].l > A[i].r)
                pref2[1]++;
        }
        if (col[i] == -1 && A[i].l > A[i].r)
        {
            pq.insert({A[i].r, i});
            era[A[i].r + 1].pb(i);
        }
    }
    for (int i = 1; i <= n; i++)
    {
        pref2[i] += pref2[i - 1];

        int id = 0;
        int r = 0;
        for (auto v : era[i])
        {
            pq.erase({i, v});
        }
        for (auto v : st[i])
        {
            if (col[v.se] == -1)
            {
                if (i > v.fi)
                {
                    pq.insert({v.fi + n, i});
                }
                else
                {
                    pq.insert({v.fi, i});
                    era[v.fi + 1].pb(i);
                }
            }
        }
        if (pref2[i] == 0)
        {
            int id = (*pq.rbegin()).se;
            int r = (*pq.rbegin()).fi;

            col[id] = 1;
            pref2[i + 1]++;
            pref2[r + 1]--;
            if (A[i].l > A[i].r)
            {
                pref2[A[i].l]++;
            }
        }
    }
    for (int i = 1; i <= m; i++)
    {
        if (col[i] == 1)
        {
            cout << 1;
        }
        else
        {
            cout << 0;
        }
    }
}

Compilation message

alternating.cpp: In function 'void dfs(int)':
alternating.cpp:60:25: warning: suggest parentheses around comparison in operand of '^' [-Wparentheses]
   60 |         else if (col[v] != col[u] ^ 1)
      |                  ~~~~~~~^~~~~~~~~
alternating.cpp: In function 'int main()':
alternating.cpp:107:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |                 while (v < check.size() && check[v] <= A[i].r)
      |                        ~~^~~~~~~~~~~~~~
alternating.cpp:117:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  117 |             while (v < check.size())
      |                    ~~^~~~~~~~~~~~~~
alternating.cpp:123:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  123 |             while (v < check.size() && check[v] <= A[i].r)
      |                    ~~^~~~~~~~~~~~~~
alternating.cpp:170:13: warning: unused variable 'id' [-Wunused-variable]
  170 |         int id = 0;
      |             ^~
alternating.cpp:171:13: warning: unused variable 'r' [-Wunused-variable]
  171 |         int r = 0;
      |             ^

Subtask #1
0 / 13.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 98124 KB Output is correct
2 Correct 43 ms 98092 KB Output is correct
3 Correct 50 ms 98096 KB Output is correct
4 Correct 46 ms 98096 KB Output is correct
5 Correct 49 ms 98192 KB Output is correct
6 Correct 50 ms 98156 KB Output is correct
7 Correct 59 ms 98104 KB Output is correct
8 Correct 48 ms 94192 KB Output is correct
9 Correct 50 ms 98124 KB Output is correct
10 Correct 51 ms 94276 KB Output is correct
11 Correct 50 ms 94188 KB Output is correct
12 Correct 51 ms 98072 KB Output is correct
13 Correct 49 ms 94372 KB Output is correct
14 Correct 46 ms 98188 KB Output is correct
15 Correct 45 ms 98084 KB Output is correct
16 Correct 45 ms 98116 KB Output is correct
17 Correct 44 ms 98192 KB Output is correct
18 Incorrect 48 ms 98156 KB no wires in direction 1 between segments 3 and 3
19 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 98124 KB Output is correct
2 Correct 43 ms 98092 KB Output is correct
3 Correct 50 ms 98096 KB Output is correct
4 Correct 46 ms 98096 KB Output is correct
5 Correct 49 ms 98192 KB Output is correct
6 Correct 50 ms 98156 KB Output is correct
7 Correct 59 ms 98104 KB Output is correct
8 Correct 48 ms 94192 KB Output is correct
9 Correct 50 ms 98124 KB Output is correct
10 Correct 51 ms 94276 KB Output is correct
11 Correct 50 ms 94188 KB Output is correct
12 Correct 51 ms 98072 KB Output is correct
13 Correct 49 ms 94372 KB Output is correct
14 Correct 46 ms 98188 KB Output is correct
15 Correct 45 ms 98084 KB Output is correct
16 Correct 45 ms 98116 KB Output is correct
17 Correct 44 ms 98192 KB Output is correct
18 Incorrect 48 ms 98156 KB no wires in direction 1 between segments 3 and 3
19 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 98124 KB Output is correct
2 Correct 43 ms 98092 KB Output is correct
3 Correct 50 ms 98096 KB Output is correct
4 Correct 46 ms 98096 KB Output is correct
5 Correct 49 ms 98192 KB Output is correct
6 Correct 50 ms 98156 KB Output is correct
7 Correct 59 ms 98104 KB Output is correct
8 Correct 48 ms 94192 KB Output is correct
9 Correct 50 ms 98124 KB Output is correct
10 Correct 51 ms 94276 KB Output is correct
11 Correct 50 ms 94188 KB Output is correct
12 Correct 51 ms 98072 KB Output is correct
13 Correct 49 ms 94372 KB Output is correct
14 Correct 46 ms 98188 KB Output is correct
15 Correct 45 ms 98084 KB Output is correct
16 Correct 45 ms 98116 KB Output is correct
17 Correct 44 ms 98192 KB Output is correct
18 Incorrect 48 ms 98156 KB no wires in direction 1 between segments 3 and 3
19 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 65 ms 102260 KB Output is correct
2 Correct 69 ms 104140 KB Output is correct
3 Correct 53 ms 96804 KB Output is correct
4 Correct 73 ms 105404 KB Output is correct
5 Correct 133 ms 109388 KB Output is correct
6 Correct 68 ms 98120 KB Output is correct
7 Incorrect 124 ms 109644 KB no wires in direction 0 between segments 1174 and 1174
8 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 44 ms 98124 KB Output is correct
2 Correct 43 ms 98092 KB Output is correct
3 Correct 50 ms 98096 KB Output is correct
4 Correct 46 ms 98096 KB Output is correct
5 Correct 49 ms 98192 KB Output is correct
6 Correct 50 ms 98156 KB Output is correct
7 Correct 59 ms 98104 KB Output is correct
8 Correct 48 ms 94192 KB Output is correct
9 Correct 50 ms 98124 KB Output is correct
10 Correct 51 ms 94276 KB Output is correct
11 Correct 50 ms 94188 KB Output is correct
12 Correct 51 ms 98072 KB Output is correct
13 Correct 49 ms 94372 KB Output is correct
14 Correct 46 ms 98188 KB Output is correct
15 Correct 45 ms 98084 KB Output is correct
16 Correct 45 ms 98116 KB Output is correct
17 Correct 44 ms 98192 KB Output is correct
18 Incorrect 48 ms 98156 KB no wires in direction 1 between segments 3 and 3
19 Halted 0 ms 0 KB -