oj.uz

답안 #749636

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
749636 2023-05-28T10:31:36 Z anhduc2701 Alternating Current (BOI18_alternating) C++17
0 / 100
 145 ms 110992 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, v.se});
                }
                else
                {
                    pq.insert({v.fi, v.se});
                    era[v.fi + 1].pb(v.se);
                }
            }
        }
        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[id].l > A[id].r)
            {
                pref2[A[id].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 48 ms 98124 KB Output is correct
2 Correct 50 ms 98192 KB Output is correct
3 Correct 45 ms 98092 KB Output is correct
4 Correct 56 ms 98092 KB Output is correct
5 Correct 54 ms 98252 KB Output is correct
6 Correct 46 ms 98124 KB Output is correct
7 Correct 46 ms 98084 KB Output is correct
8 Correct 45 ms 94212 KB Output is correct
9 Correct 45 ms 98252 KB Output is correct
10 Correct 44 ms 94244 KB Output is correct
11 Correct 45 ms 94196 KB Output is correct
12 Correct 50 ms 98184 KB Output is correct
13 Correct 45 ms 94260 KB Output is correct
14 Correct 48 ms 98096 KB Output is correct
15 Correct 47 ms 98072 KB Output is correct
16 Correct 47 ms 98252 KB Output is correct
17 Correct 48 ms 98084 KB Output is correct
18 Correct 52 ms 98112 KB Output is correct
19 Correct 52 ms 98216 KB Output is correct
20 Correct 47 ms 98116 KB Output is correct
21 Correct 46 ms 98132 KB Output is correct
22 Correct 46 ms 98160 KB Output is correct
23 Correct 48 ms 98092 KB Output is correct
24 Correct 47 ms 98188 KB Output is correct
25 Correct 51 ms 98124 KB Output is correct
26 Correct 45 ms 98128 KB Output is correct
27 Incorrect 52 ms 98196 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #2
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 48 ms 98124 KB Output is correct
2 Correct 50 ms 98192 KB Output is correct
3 Correct 45 ms 98092 KB Output is correct
4 Correct 56 ms 98092 KB Output is correct
5 Correct 54 ms 98252 KB Output is correct
6 Correct 46 ms 98124 KB Output is correct
7 Correct 46 ms 98084 KB Output is correct
8 Correct 45 ms 94212 KB Output is correct
9 Correct 45 ms 98252 KB Output is correct
10 Correct 44 ms 94244 KB Output is correct
11 Correct 45 ms 94196 KB Output is correct
12 Correct 50 ms 98184 KB Output is correct
13 Correct 45 ms 94260 KB Output is correct
14 Correct 48 ms 98096 KB Output is correct
15 Correct 47 ms 98072 KB Output is correct
16 Correct 47 ms 98252 KB Output is correct
17 Correct 48 ms 98084 KB Output is correct
18 Correct 52 ms 98112 KB Output is correct
19 Correct 52 ms 98216 KB Output is correct
20 Correct 47 ms 98116 KB Output is correct
21 Correct 46 ms 98132 KB Output is correct
22 Correct 46 ms 98160 KB Output is correct
23 Correct 48 ms 98092 KB Output is correct
24 Correct 47 ms 98188 KB Output is correct
25 Correct 51 ms 98124 KB Output is correct
26 Correct 45 ms 98128 KB Output is correct
27 Incorrect 52 ms 98196 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #3
0 / 22.0

# 결과 실행 시간 메모리 Grader output
1 Correct 48 ms 98124 KB Output is correct
2 Correct 50 ms 98192 KB Output is correct
3 Correct 45 ms 98092 KB Output is correct
4 Correct 56 ms 98092 KB Output is correct
5 Correct 54 ms 98252 KB Output is correct
6 Correct 46 ms 98124 KB Output is correct
7 Correct 46 ms 98084 KB Output is correct
8 Correct 45 ms 94212 KB Output is correct
9 Correct 45 ms 98252 KB Output is correct
10 Correct 44 ms 94244 KB Output is correct
11 Correct 45 ms 94196 KB Output is correct
12 Correct 50 ms 98184 KB Output is correct
13 Correct 45 ms 94260 KB Output is correct
14 Correct 48 ms 98096 KB Output is correct
15 Correct 47 ms 98072 KB Output is correct
16 Correct 47 ms 98252 KB Output is correct
17 Correct 48 ms 98084 KB Output is correct
18 Correct 52 ms 98112 KB Output is correct
19 Correct 52 ms 98216 KB Output is correct
20 Correct 47 ms 98116 KB Output is correct
21 Correct 46 ms 98132 KB Output is correct
22 Correct 46 ms 98160 KB Output is correct
23 Correct 48 ms 98092 KB Output is correct
24 Correct 47 ms 98188 KB Output is correct
25 Correct 51 ms 98124 KB Output is correct
26 Correct 45 ms 98128 KB Output is correct
27 Incorrect 52 ms 98196 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -

Subtask #4
0 / 19.0

# 결과 실행 시간 메모리 Grader output
1 Correct 86 ms 106632 KB Output is correct
2 Correct 72 ms 104096 KB Output is correct
3 Correct 57 ms 96876 KB Output is correct
4 Correct 75 ms 105548 KB Output is correct
5 Correct 138 ms 109556 KB Output is correct
6 Correct 73 ms 98336 KB Output is correct
7 Correct 128 ms 109840 KB Output is correct
8 Correct 60 ms 102600 KB Output is correct
9 Correct 58 ms 101920 KB Output is correct
10 Correct 145 ms 110860 KB Output is correct
11 Correct 110 ms 109260 KB Output is correct
12 Correct 123 ms 110992 KB Output is correct
13 Incorrect 58 ms 104144 KB no wires in direction 0 between segments 100000 and 100000
14 Halted 0 ms 0 KB -

Subtask #5
0 / 26.0

# 결과 실행 시간 메모리 Grader output
1 Correct 48 ms 98124 KB Output is correct
2 Correct 50 ms 98192 KB Output is correct
3 Correct 45 ms 98092 KB Output is correct
4 Correct 56 ms 98092 KB Output is correct
5 Correct 54 ms 98252 KB Output is correct
6 Correct 46 ms 98124 KB Output is correct
7 Correct 46 ms 98084 KB Output is correct
8 Correct 45 ms 94212 KB Output is correct
9 Correct 45 ms 98252 KB Output is correct
10 Correct 44 ms 94244 KB Output is correct
11 Correct 45 ms 94196 KB Output is correct
12 Correct 50 ms 98184 KB Output is correct
13 Correct 45 ms 94260 KB Output is correct
14 Correct 48 ms 98096 KB Output is correct
15 Correct 47 ms 98072 KB Output is correct
16 Correct 47 ms 98252 KB Output is correct
17 Correct 48 ms 98084 KB Output is correct
18 Correct 52 ms 98112 KB Output is correct
19 Correct 52 ms 98216 KB Output is correct
20 Correct 47 ms 98116 KB Output is correct
21 Correct 46 ms 98132 KB Output is correct
22 Correct 46 ms 98160 KB Output is correct
23 Correct 48 ms 98092 KB Output is correct
24 Correct 47 ms 98188 KB Output is correct
25 Correct 51 ms 98124 KB Output is correct
26 Correct 45 ms 98128 KB Output is correct
27 Incorrect 52 ms 98196 KB no wires in direction 0 between segments 15 and 15
28 Halted 0 ms 0 KB -