Submission #991367

#	Time	Username	Problem	Language	Result	Execution time	Memory
991367		PCTprobability	Seats (IOI18_seats)	C++17	25 / 100	3427 ms	203536 KiB

seats

#include "seats.h"
#include <bits/stdc++.h>
using namespace std;
struct nd{
  int mx,mn;
  nd(){
    mx=0;
    mn=10000;
  }
  nd(int a,int b){
    mx=a,mn=b;
  }
};
nd merge(nd a,nd b){
  return nd(max(a.mx,b.mx),min(a.mn,b.mn));
}
struct segtree{
  vector<nd> node;
  int n;
  segtree(){
  }
  segtree(int n_,vector<int> a){
    n=1;
    while(n<n_) n*=2;
    node.resize(2*n);
    for(int i=0;i<2*n;i++) node[i]=nd();
    for(int i=0;i<n_;i++) node[i+n]=nd(a[i],a[i]);
    for(int i=n-1;i>=0;i--) node[i]=merge(node[2*i],node[2*i+1]);
  }
  void set(int x,int v){
    x+=n;
    node[x]=nd(v,v);
    while(x>1){
      x/=2;
      node[x]=merge(node[2*x],node[2*x+1]);
    }
  }
  nd prod(int l,int r,int a,int b,int k){
    if(r<=a||b<=l) return nd();
    if(l<=a&&b<=r) return node[k];
    return merge(prod(l,r,a,(a+b)/2,2*k),prod(l,r,(a+b)/2,b,2*k+1));
  }
  nd prod(int l,int r){
    return prod(l,r,0,n,1);
  }
};
int r[1010101],c[1010101];
segtree rsg,csg;
int n,m;
int ans=0;
set<int> rs[1010],cs[1010];
void give_initial_chart(int H, int W, std::vector<int> R, std::vector<int> C) {
  n=H,m=W;
  for(int i=0;i<n*m;i++){
    r[i]=R[i];
    c[i]=C[i];
    rs[r[i]].insert(i);
    cs[c[i]].insert(i);
  }
  segtree se(n*m,R),se3(n*m,C);
  rsg=se,csg=se3;
}
 
int swap_seats(int a, int b) {
  int ans=0;
  rs[r[a]].erase(a);
  cs[c[a]].erase(a);
  rs[r[b]].erase(b);
  cs[c[b]].erase(b); 
  swap(r[a],r[b]);
  swap(c[a],c[b]);
  rs[r[a]].insert(a);
  rs[r[b]].insert(b);
  cs[c[a]].insert(a);
  cs[c[b]].insert(b);
  rsg.set(a,r[a]);
  rsg.set(b,r[b]);
  csg.set(a,c[a]);
  csg.set(b,c[b]);
  set<int> idx;
  vector<int> w;
  for(int i=0;i<n;i++) w.push_back(*rs[i].begin());
  for(int i=0;i<m;i++) w.push_back(*cs[i].begin());
  w.push_back(n*m);
  sort(w.begin(),w.end());
  for(int i=0;i<w.size();i++){
    if(i&&w[i]==w[i-1]) continue;
    int t=w[i]-1;
    if(t<0) continue;
    nd p=rsg.prod(0,t+1),q=csg.prod(0,t+1);
    if((p.mx-p.mn+1)*(q.mx-q.mn+1)==t+1) ans++;
  }
  return ans;
}

Compilation message (stderr)

seats.cpp: In function 'int swap_seats(int, int)':
seats.cpp:86:16: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   86 |   for(int i=0;i<w.size();i++){
      |               ~^~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 0 / 6
• Subtask 3: 20 / 20
• Subtask 4: 0 / 6
• Subtask 5: 0 / 33
• Subtask 6: 0 / 30