Go: package main

import "fmt"

func main() {
	//部屋を生成
	var H int

	fmt.Scan(&H)
	room := [][4]bool{}

	for i := 0; i < H; i++ {
		room = append(room, [4]bool{})
	}

	//荷物のおけない区画を設定
	var N int
	fmt.Scan(&N)
	for i := 0; i < N; i++ {
		var x, y int
		fmt.Scan(&x, &y)
		room[y][x] = true //ものがある状態を真とする
	}
	//荷物を配置
	var count int
	for j := 0; j < H-1; j++ {
		for i := 0; i < 3; i++ {

			if !room[j][i] && !room[j+1][i] && !room[j][i+1] && !room[j+1][i+1] {
				//if i!=0&&i!=2&&j!=H-3{
				//	if !room[j+1][i-1]&&!room[j+1][i+2]{
				//		if !room[j+2][0]&&!room[j+2][1]&&!room[j+2][2]&&!room[j+2][3]{
				//			break
				//		}
				//	}
				//}
				room[j][i] = true
				room[j+1][i] = true
				room[j][i+1] = true
				room[j+1][i+1] = true
				count++
			}
		}
	}

	var openCount int
	for _,v:=range room{
		openCount=0
		for _,v2:=range v{
			if !v2{
				openCount++
			}

		}
		if openCount>=3{
			count++
		}
	}
	fmt.Println(count)
}

C++: #include<bits/stdc++.h>
using namespace std;
bool mp[10005][4];

int main(){
  ios_base::sync_with_stdio(false);
  int h,n,x,y;
  for(int i=0;i<10005;i++){
    for(int j=0;j<4;j++){
      mp[i][j] = true;
    }
  }
  cin >> h >> n;
  
  for(int i=0;i<n;i++){
    cin >> x >> y;
    mp[y][x] = false;
  }

  int ans = 0;
  for(int i=0;i<h-1;i++){
    if(mp[i][0] && mp[i][1] && mp[i+1][0] && mp[i+1][1]){ //左に正方形が作れるとき
      mp[i][0] = mp[i][1] = mp[i+1][0] = mp[i+1][1] = false;
      ans++;
    }
    if(mp[i][2] && mp[i][3] && mp[i+1][2] && mp[i+1][3]){ //右に正方形が作れるとき
      mp[i][2] = mp[i][3] = mp[i+1][2] = mp[i+1][3] = false;
      ans++;
    }
    if(mp[i][1] && mp[i][2] && mp[i+1][1] && mp[i+1][2]){ //真ん中に正方形が作れるとき
      int j=0;
      while(i+1+j < h && mp[i+1+j][0] && mp[i+1+j][1] && mp[i+1+j][2] && mp[i+1+j][3]) j++;
      if(j != 0 && j%2 == 1){
	mp[i][1] = mp[i][2] = mp[i+1][1] = mp[i+1][2] = false;
	ans++;
      }
    }
  }

  cout << ans << endl;

  return 0;
}

C++: #include<iostream>
#include<algorithm>
bool m[4][10010];
int dp[100010];
int main(){
	int H, N;
	std::cin >> H >> N;
	for(int i = 0; i < N; i++){
		int x, y;
		std::cin >> x >> y;
		m[x][y] = true;
	}
	for(int i = 0; i < H - 1; i++){
		int res1 = 0;
		if((!m[0][i]) && (!m[1][i]) && (!m[0][i + 1]) && (!m[1][i + 1]))res1++;
		if((!m[2][i]) && (!m[3][i]) && (!m[2][i + 1]) && (!m[3][i + 1]))res1++;
		int res2 = 0;
		if((!m[1][i]) && (!m[2][i]) && (!m[1][i + 1]) && (!m[2][i + 1]))res2++;
		dp[i] += std::max(res1, res2);
		dp[i + 2] = std::max(dp[i], dp[i + 2]);
		dp[i + 3] = std::max(dp[i], dp[i + 3]);
	}
	std::cout << std::max(dp[H - 2], dp[H - 1]) << std::endl;
	return 0;
}

C++: #include <bits/stdc++.h>

using namespace std;

using i64 = int64_t;
const i64 MOD = 1e9 + 7;
const i64 INF = i64(1e18) + 7;


signed main(){
    int h, n;
    cin >> h >> n;
    vector<bitset<8>> bs(h);
    for(int i = 0; i < n; ++i){
        int x, y;
        cin >> y >> x;
        bs[x].set(y);
        if(x)
            bs[x - 1].set(y + 4);
    }


    vector<pair<int, int>> mask_vec{
        make_pair(bitset<8>("00000000").to_ulong(), 0),
        make_pair(bitset<8>("11001100").to_ulong(), 1),
        make_pair(bitset<8>("01100110").to_ulong(), 1),
        make_pair(bitset<8>("00110011").to_ulong(), 1),
        make_pair(bitset<8>("11111111").to_ulong(), 2)
    };

    vector<vector<int>> dp(h, vector<int>(256, 0));
    for(int i = 0; i < h - 1; ++i){
        for(int j = 0; j < 256; ++j){
            if(j & bs[i].to_ulong())
                continue;
            for(auto& mask : mask_vec){
                if((j | bs[i].to_ulong()) & mask.first)
                    continue;
                int nex = (j | mask.first) >> 4;
                dp[i + 1][nex] = max(dp[i + 1][nex], dp[i][j] + mask.second);
            }
        }
    }
    int ans = 0;
    for(int j = 0; j < 256; ++j){
        if((j & bs.back().to_ulong()) == 0)
            ans = max(ans, dp.back()[j]);
    }
    cout << ans << endl;

}

C++: #include <iostream>
#include <algorithm>
#include <vector>
#include <queue>
#include <set>
#include <string>
#include <stack>
#include <cmath>
#define ll long long
#define FOR(i,a,b) for(int i=a;i<b;i++)
#define ROF(i,a,b) for(int i=b-1;i>=a;i--)
using namespace std;
//
const int inf=1e9+7;
const int mod=1e9+7;
//
struct poi{
	int X;int Y;int Z;
	bool operator<(const poi&R)const{
		return X==R.X ? Y==R.Y ? Z<R.Z : Y<R.Y : X<R.X;
	}
};
//
ll GCD(ll a,ll b){
	return (b==0)?(a):(GCD(b,a%b));
}
ll LCM(ll a,ll b){
	return a/GCD(a,b)*b;
}
//
int H,N;
int ok[20000][4];
int DP[20000][5];
int main(){
	cin>>H>>N;
	FOR(i,0,H){
		FOR(j,0,4){
			ok[i][j]=1;
		}
	}
	FOR(i,0,N){
		int X,Y;
		cin>>X>>Y;
		ok[Y][X]=0;
	}
	/*
	cout<<endl;
	FOR(i,0,H){
		FOR(j,0,4){
			cout<<ok[i][j]<<" ";
		}
		cout<<endl;
	}
	cout<<endl;
	*/
	//
	if(ok[0][0]&&ok[0][1]&&ok[1][0]&&ok[1][1]){
		DP[0][1]=1;
	}
	if(ok[0][1]&&ok[0][2]&&ok[1][1]&&ok[1][2]){
		DP[0][2]=1;
	}
	if(ok[0][2]&&ok[0][3]&&ok[1][2]&&ok[1][3]){
		DP[0][3]=1;
	}
	if(ok[0][0]&&ok[0][1]&&ok[1][0]&&ok[1][1]&&ok[0][2]&&ok[0][3]&&ok[1][2]&&ok[1][3]){
		DP[0][4]=2;
	}
	//
	if(ok[1][0]&&ok[1][1]&&ok[2][0]&&ok[2][1]){
		DP[1][1]=DP[0][3]+1;
	}
	if(ok[1][1]&&ok[1][2]&&ok[2][1]&&ok[2][2]){
		DP[1][2]=1;
	}
	if(ok[1][2]&&ok[1][3]&&ok[2][2]&&ok[2][3]){
		DP[1][3]=DP[0][1]+1;
	}
	if(ok[1][0]&&ok[1][1]&&ok[2][0]&&ok[2][1]&&ok[1][2]&&ok[1][3]&&ok[2][2]&&ok[2][3]){
		DP[1][4]=2;
	}
	//
	FOR(i,2,H-1){
		DP[i][0]=max({DP[i-2][0],DP[i-2][1],DP[i-2][2],DP[i-2][3],DP[i-2][4]});
		DP[i][0]=max({DP[i][0],DP[i-1][0],DP[i-1][1],DP[i-1][2],DP[i-1][3],DP[i-1][4]});
		DP[i][1]=max({DP[i][0],DP[i-1][3],DP[i-2][0],DP[i-2][1],DP[i-2][2],DP[i-2][3],DP[i-2][4]});
		DP[i][2]=max({DP[i][0],DP[i-2][0],DP[i-2][1],DP[i-2][2],DP[i-2][3],DP[i-2][4]});
		DP[i][3]=max({DP[i][0],DP[i-1][1],DP[i-2][0],DP[i-2][1],DP[i-2][2],DP[i-2][3],DP[i-2][4]});
		DP[i][4]=max({DP[i][0],DP[i-2][0],DP[i-2][1],DP[i-2][2],DP[i-2][3],DP[i-2][4]});
		if(ok[i][0]&&ok[i][1]&&ok[i+1][0]&&ok[i+1][1]){
			DP[i][1]++;
		}else{
			DP[i][1]=max({DP[i][1],DP[i-1][0],DP[i-1][1],DP[i-1][2],DP[i-1][3],DP[i-1][4]});
		}
		if(ok[i][1]&&ok[i][2]&&ok[i+1][1]&&ok[i+1][2]){
			DP[i][2]++;
		}else{
			DP[i][2]=max({DP[i][2],DP[i][0],DP[i-1][0],DP[i-1][1],DP[i-1][2],DP[i-1][3],DP[i-1][4]});
		}
		if(ok[i][2]&&ok[i][3]&&ok[i+1][2]&&ok[i+1][3]){
			DP[i][3]++;
		}else{
			DP[i][3]=max({DP[i][3],DP[i-1][0],DP[i-1][1],DP[i-1][2],DP[i-1][3],DP[i-1][4]});
		}
		if(ok[i][0]&&ok[i][1]&&ok[i+1][0]&&ok[i+1][1]&&ok[i][2]&&ok[i][3]&&ok[i+1][2]&&ok[i+1][3]){
			DP[i][4]+=2;
		}else{
			DP[i][4]=max({DP[i][4],DP[i][0],DP[i-1][0],DP[i-1][1],DP[i-1][2],DP[i-1][3],DP[i-1][4]});
		}
	}
	int ans=0;
	/*
	FOR(i,0,H){
		FOR(j,0,5){
			cout<<DP[i][j]<<" ";
		}
		cout<<endl;
	}
	cout<<endl;
	*/
	FOR(i,0,5){
		ans=max(ans,DP[H-2][i]);
	}
	cout<<ans<<endl;
	return 0;
}