Submission #875194

#	Time	Username	Problem	Language	Result	Execution time	Memory
875194		abcvuitunggio	Seats (IOI18_seats)	C++17	33 / 100	451 ms	69536 KiB

seats

#include "seats.h"
#include <bits/stdc++.h>
using namespace std;
struct T{
    int mn,cnt,sum;
}st[4000001];
int n;
vector <int> r,c;
vector <vector <int>> a;
T operator +(T a, T b){
    T c;
    c.mn=min(a.mn,a.sum+b.mn);
    if (a.mn==a.sum+b.mn)
        c.cnt=a.cnt+b.cnt;
    else if (a.mn<a.sum+b.mn)
        c.cnt=a.cnt;
    else
        c.cnt=b.cnt;
    c.sum=a.sum+b.sum;
    return c;
}
int cell(int i, int j){
    return (i<0||i>=a.size()||j<0||j>=a[0].size()?n:a[i][j]);
}
pair <int, int> best(int i, int j){
    int x=n,y=n;
    for (int k=0;k<2;k++)
        for (int l=0;l<2;l++){
            int val=cell(i+k,j+l);
            if (val<x){
                y=x;
                x=val;
            }
            else
                y=min(y,val);
        }
    return {x,y};
}
int calc(int i){
    int res=0;
    for (int j=0;j<2;j++)
        for (int k=0;k<2;k++){
            auto [x,y]=best(r[i]-j,c[i]-k);
            res+=(i==x)-(i==y);
        }
    return res;
}
void build(int node, int l, int r){
    if (l==r){
        st[node]={calc(l),1,calc(l)};
        return;
    }
    int mid=(l+r)>>1;
    build(node<<1,l,mid);
    build(node<<1|1,mid+1,r);
    st[node]=st[node<<1]+st[node<<1|1];
}
void update(int node, int l, int r, int i){
    if (l>i||r<i||l>r)
        return;
    if (l==r){
        st[node]={calc(i),1,calc(i)};
        return;
    }
    int mid=(l+r)>>1;
    update(node<<1,l,mid,i);
    update(node<<1|1,mid+1,r,i);
    st[node]=st[node<<1]+st[node<<1|1];
}
void give_initial_chart(int H, int W, vector <int> R, vector <int> C){
    r=R;
    c=C;
    n=H*W;
    a.resize(H);
    for (int i=0;i<H;i++)
        a[i].assign(W,0);
    for (int i=0;i<n;i++)
        a[r[i]][c[i]]=i;
    build(1,0,n-1);
}
int swap_seats(int x, int y){
    swap(r[x],r[y]);
    swap(c[x],c[y]);
    swap(a[r[x]][c[x]],a[r[y]][c[y]]);
    for (int i=-1;i<2;i++){
        update(1,0,n-1,cell(r[x]+i,c[x]));
        update(1,0,n-1,cell(r[x],c[x]+i));
        update(1,0,n-1,cell(r[y]+i,c[y]));
        update(1,0,n-1,cell(r[y],c[y]+i));
    }
    return st[1].cnt;
}

Compilation message (stderr)

seats.cpp: In function 'int cell(int, int)':
seats.cpp:23:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     return (i<0||i>=a.size()||j<0||j>=a[0].size()?n:a[i][j]);
      |                  ~^~~~~~~~~~
seats.cpp:23:37: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   23 |     return (i<0||i>=a.size()||j<0||j>=a[0].size()?n:a[i][j]);
      |                                    ~^~~~~~~~~~~~~

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