Submission #293020

#	Time	Username	Problem	Language	Result	Execution time	Memory
293020		BThero	Port Facility (JOI17_port_facility)	C++17	78 / 100	6125 ms	949852 KiB

port_facility

// chrono::system_clock::now().time_since_epoch().count()
#include<bits/stdc++.h>
 
#define pb push_back
#define eb emplace_back
#define mp make_pair
#define fi first
#define se second
#define all(x) (x).begin(), (x).end()
#define debug(x) cerr << #x << " = " << x << endl;
 
using namespace std;
 
typedef long long ll;
typedef pair<int, int> pii;
 
const int MAXN = (int)2e6 + 5;
const int MOD = (int)1e9 + 7;
 
vector<pii> lt[MAXN << 2], rt[MAXN << 2];
int col[MAXN];
pii arr[MAXN];
int n;
 
bool cmp(pii a, pii b) {
  return a.se < b.se;
}
 
void addL(int v, int tl, int tr, int l, int r, int id) {
  lt[v].pb(mp(r, id));
 
  if (tl == tr) {
    return;
  }
  
  int mid = (tl + tr) >> 1;
  int c1 = (v << 1), c2 = (c1 | 1);
  
  if (l <= mid) {
    addL(c1, tl, mid, l, r, id);
  }
  else {
    addL(c2, mid + 1, tr, l, r, id);
  }
}

void addR(int v, int tl, int tr, int l, int r, int id) {
  rt[v].pb(mp(l, id));
 
  if (tl == tr) {
    return;
  }
  
  int mid = (tl + tr) >> 1;
  int c1 = (v << 1), c2 = (c1 | 1);
  
  if (r <= mid) {
    addR(c1, tl, mid, l, r, id);
  }
  else {
    addR(c2, mid + 1, tr, l, r, id);
  }
}

void prep(int v, int tl, int tr) {
  sort(all(lt[v]));
  sort(all(rt[v]));
  reverse(all(rt[v]));
  
  if (tl != tr) {
    int mid = (tl + tr) >> 1;
    int c1 = (v << 1), c2 = (c1 | 1);
    prep(c1, tl, mid);
    prep(c2, mid + 1, tr);
  }
}

void goL(int v, int tl, int tr, int l, int r, int lim, vector<int> &e) {
  if (l > r || tl > r || tr < l) {
    return;
  }
  
  if (l <= tl && tr <= r) {
    while (!lt[v].empty() && lt[v].back().fi >= lim) {
      e.pb(lt[v].back().se);
      lt[v].pop_back();
    }
    
    return;
  }
  
  int mid = (tl + tr) >> 1;
  int c1 = (v << 1), c2 = (c1 | 1);
  goL(c1, tl, mid, l, r, lim, e);
  goL(c2, mid + 1, tr, l, r, lim, e);
}

void goR(int v, int tl, int tr, int l, int r, int lim, vector<int> &e) {
  if (l > r || tl > r || tr < l) {
    return;
  }
  
  if (l <= tl && tr <= r) {
    while (!rt[v].empty() && rt[v].back().fi <= lim) {
      e.pb(rt[v].back().se);
      rt[v].pop_back();
    }
    
    return;
  }
  
  int mid = (tl + tr) >> 1;
  int c1 = (v << 1), c2 = (c1 | 1);
  goR(c1, tl, mid, l, r, lim, e);
  goR(c2, mid + 1, tr, l, r, lim, e);
}
 
void dfs(int v) {
  vector<int> e;
  goL(1, 1, 2 * n, arr[v].fi + 1, arr[v].se - 1, arr[v].se + 1, e);
  goR(1, 1, 2 * n, arr[v].fi + 1, arr[v].se - 1, arr[v].fi - 1, e);
  
  for (int to : e) {
    if (col[to] == -1) {
      col[to] = 1 - col[v];
      dfs(to);
    }
    else if (col[to] == col[v]) {
      printf("0\n");
      exit(0);
    }
  }
}
 
void solve() {
  scanf("%d", &n);
  
  for (int i = 1; i <= n; ++i) {
    scanf("%d %d", &arr[i].fi, &arr[i].se);
  }
  
  sort(arr + 1, arr + n + 1, cmp);
  
  for (int i = 1; i <= n; ++i) {
    addL(1, 1, 2 * n, arr[i].fi, arr[i].se, i);
    addR(1, 1, 2 * n, arr[i].fi, arr[i].se, i);
  }
  
  prep(1, 1, 2 * n);
  fill(col + 1, col + n + 1, -1);
  int ans = 1;
  
  for (int i = 1; i <= n; ++i) {
    if (col[i] == -1) {
      col[i] = 0;
      dfs(i);
      ans = (ans * 2) % MOD;
    }
  }
  
  printf("%d\n", ans);
}
 
int main() {
  int tt = 1;
  
  while (tt--) {
    solve();
  }
 
  return 0;
}

Compilation message (stderr)

port_facility.cpp: In function 'void solve()':
port_facility.cpp:136:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  136 |   scanf("%d", &n);
      |   ~~~~~^~~~~~~~~~
port_facility.cpp:139:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  139 |     scanf("%d %d", &arr[i].fi, &arr[i].se);
      |     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 56 / 56
• Subtask 4: 0 / 22