Submission #292857

#	Time	Username	Problem	Language	Result	Execution time	Memory
292857		BThero	Port Facility (JOI17_port_facility)	C++17	22 / 100	6040 ms	34528 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)2e5 + 5;
const int MOD = (int)1e9 + 7;

int addMod(int a, int b, int m = MOD) {
  a += b;
  
  if (m <= a) {
    a -= m;
  }
  
  return a;
}

int mulMod(int a, int b, int m = MOD) {
  return a * 1ll * b % m;
}

vector<int> t[MAXN << 2];
pii arr[MAXN];
int n;

namespace DSU {
  int par[MAXN], sz[MAXN], up[MAXN];
  
  void init(int n) {
    for (int i = 1; i <= n; ++i) {
      par[i] = i;
      sz[i] = 1;
      up[i] = 0;
    }
  }
  
  int get(int x, int &col) {
    while (x != par[x]) {
      col ^= up[x];
      x = par[x];
    }
    
    return x;
  }
  
  bool uni(int a, int b) {
    int path = 0;
    int na = get(a, path);
    int nb = get(b, path);
    
    if (na == nb) {
      return path == 1;
    }
    
    if (sz[na] < sz[nb]) {
      swap(a, b);
      swap(na, nb);
    }
    
    sz[na] += sz[nb];
    par[nb] = na;
    up[nb] = 1 - path;
    return 1;
  }
  
  int ans() {
    int ret = 1;
    
    for (int i = 1; i <= n; ++i) {
      if (par[i] == i) {
        ret = addMod(ret, ret);
      }
    }
    
    return ret;
  }
};

bool cmp(pii a, pii b) {
  return a.se < b.se;
}

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

void go(int v, int tl, int tr, int p, int id) {
  int sz = (int)t[v].size();

  for (int i = 0; i < sz; ++i) {
    if (!DSU::uni(t[v][sz - i - 1], id)) {
      printf("0\n");
      exit(0);
    }
  }
  
  if (tl != tr) {
    int mid = (tl + tr) >> 1;
    int c1 = (v << 1), c2 = (c1 | 1);
    
    if (p <= mid) {
      go(c1, tl, mid, p, id);
    }
    else {
      go(c2, mid + 1, tr, p, id);
    }
  }
}

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);
  DSU::init(n);
  
  for (int i = 1; i <= n; ++i) {
    go(1, 1, 2 * n, arr[i].fi, i);
    update(1, 1, 2 * n, arr[i].fi + 1, arr[i].se - 1, i);
  }
  
  printf("%d\n", DSU::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: 0 / 56
• Subtask 4: 0 / 22