Submission #468205

#	Time	Username	Problem	Language	Result	Execution time	Memory
468205		nathanlee726	Building 4 (JOI20_building4)	C++14	0 / 100	3 ms	1356 KiB

building4

//#include<i_am_noob_orz>
#include<bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
using namespace __gnu_pbds;
using namespace std;
#define ll long long
#define int ll
#define ull unsigned long long
#define pii pair<int,int>
#define X first
#define Y second
#define mod ((ll)1e9+7)
#define pb push_back
#define mp make_pair
#define abs(x) ((x)>0?(x):(-(x)))
#define F(n) Fi(i,n)
#define Fi(i,n) Fl(i,0,n)
#define Fl(i,l,n) for(int i=l;i<n;i++)
#define memres(a) memset(a,0,sizeof(a))
#define all(a) a.begin(),a.end()
#define sz(a) ((int)a.size())
#define ceiling(a,b) (((a)+(b)-1)/(b))
#define endl '\n'
#define bit_count(x) __builtin_popcountll((x))
#define ykh mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());
#define jimmy_is_kind false
typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> rbtree;

#undef LOCAL
//#define LOCAL
#ifdef LOCAL
#define bug(...) cerr<<"#"<<__LINE__<<' '<<#__VA_ARGS__<<"- ", _do(__VA_ARGS__)
template<typename T> void _do(T && x) {cerr<<x<<endl;}
template<typename T, typename ...S> void _do(T && x, S&&...y) {cerr<<x<<", "; _do(y...);}
#define IOS()
#else
#define IOS() ios_base::sync_with_stdio(0), cin.tie(0)
#define endl '\n'
#define bug(...)
#endif
 
int add(int a,int b){return(a+b>=mod?a+b-mod:a+b);}
int sub(int a,int b){return(a<b?a+mod-b:a-b);}
int po(int a,int b){
	if(b==0)return 1;
	if(b==1)return(a%mod);
	int tem=po(a,b/2);
	if(b&1)return(((tem*tem)%mod)*a)%mod;
	else return(tem*tem)%mod; 
}
int GCD(int a,int b){
	int x=0;
	int ra,rb;
	while(a&&b){
		if(((a&1)==0)&&((b&1)==0)){
			a>>=1,b>>=1,x++;
		}
		else if((a^b)&1){
			if(a&1)b>>=1;
			else a>>=1;
		}
		else{
			ra=abs(a-b),rb=min(a,b);
			a=ra,b=rb;
		}
	}
	return max(a,b)<<x;
}
int gcd(int a,int b){if(b==0)return a;return gcd(b,a%b);}
int n,N;
int a[1000010],b[1000010];
bool ttag[1000010];
vector<int> o;
signed main(){
	freopen("01-11.txt","r",stdin);
	IOS();
	cin>>n;
	N=n*2;
	F(N)cin>>a[i];
	F(N)cin>>b[i];
	int np=-1e9;
	int x=0;
	bool tag=0,flag=0;
	memres(ttag);
	F(N){
		if(a[i]<=b[i]){
			if(a[i]>=np){
				np=a[i];
				x++;
				o.pb(0);
			}
			else if(b[i]>=np){
				np=b[i];
				o.pb(1);
			}
			else{
				tag=1;
				break;
			}
		}
		else{
			if(b[i]>=np){
				np=b[i];
				o.pb(1);
			}
			else if(a[i]>=np){
				np=a[i];
				x++;
				o.pb(0);
			}
			else{
				tag=1;
				break;
			}
		}
	}
	bug(x);
	if(tag){
		cout<<"-1"<<endl;
		return 0;
	}
	bug("c");
	if(x<n){
		x=N-x;
		swap(a,b);
		F(N)o[i]=1-o[i];
		flag=1;
	}
	vector<int> v,s(N);
	for(int i=N-1;i>=0;i--){
		if(i==N-1){
			v.pb(i); 
			if(o[i]==0){
				if(b[i]>=a[i]){
					s[i]=1;
				}
				else{
					s[i]=0;
				}
			}
			else{
				if(a[i]>=b[i]){
					s[i]=-1;
				}
				else{
					s[i]=0;
				}
			}
		}
		else{
			if(o[i]==0){
				if(b[i]>=a[i]){
					if(s[i+1]==1){
						if(b[i]<=a[i+1]){
							s[i]=1;
							v.pb(i);
						}
						else if(b[i]<=b[i+1]){
							s[i]=1;
						}
						else{
							s[i]=0;
							v.pb(i);
						}
					}
					else if(s[i+1]==-1){
						if(b[i]<=b[i+1]){
							s[i]=1;
							v.pb(i);
						}
						else if(b[i]<=a[i+1]){
							s[i]=1;
						}
						else{
							s[i]=0;
							v.pb(i);
						}
					}
					else{
						if(o[i+1]==0){
							if(b[i]<=a[i+1]){
								s[i]=1;
								v.pb(i);
							}
							else{
								s[i]=0;
								v.pb(i);
							}
						}
						else{
							if(b[i]<=b[i+1]){
								s[i]=1;
								v.pb(i);
							}
							else{
								s[i]=0;
								v.pb(i);
							}
						}
					}
				}
				else{
					s[i]=0;
					v.pb(i);
				}
			}
			else{
				if(a[i]>=b[i]){
					if(s[i+1]==1){
						if(a[i]<=a[i+1]){
							s[i]=-1;
							v.pb(i);
						}
						else if(a[i]<=b[i+1]){
							s[i]=-1;
						}
						else{
							s[i]=0;
							v.pb(i);
						}
					}
					else if(s[i+1]==-1){
						if(a[i]<=b[i+1]){
							s[i]=-1;
							v.pb(i);
						}
						else if(a[i]<=a[i+1]){
							s[i]=-1;
						}
						else{
							s[i]=0;
							v.pb(i);
						}
					}
					else{
						if(o[i+1]==0){
							if(a[i]<=a[i+1]){
								s[i]=-1;
								v.pb(i);
							}
							else{
								s[i]=0;
								v.pb(i);
							}
						}
						else{
							if(a[i]<=b[i+1]){
								s[i]=-1;
								v.pb(i);
							}
							else{
								s[i]=0;
								v.pb(i);
							}
						}
					}
				}
				else{
					s[i]=0;
					v.pb(i);
				}
			}
		}
	}
	int co=x-n;
	bug(sz(v),co);
	F(sz(v)){
		if(co==0)break;
		bug(v[i]);
		int l,r;
		if(i==sz(v)-1){
			l=0,r=v[i];
		}
		else{
			l=v[i+1]+1,r=v[i];
		}
		int ma=0,mip=-1,no=0;
		for(int j=r;j>=l;j--){
			no+=s[j];
			if(no>ma){
				ma=no,mip=j;
			}
			if(ma==co)break;
		}
		if(ma>0){
			for(int j=mip;j<=r;j++){
				if(s[j]!=0){
					o[j]=1-o[j];
				}
			}
		}
		co-=ma;
		if(co==0)break;
	}
	F(N)bug(s[i]);
	//cout<<co<<endl;
	if(co!=0){
		cout<<"-1"<<endl;
		return 0;
	}
	for(int i:o){
		if(flag)i=1-i;
		cout<<(i?'B':'A'); 
	}
	cout<<endl;
	return 0;
}
/*
3
6 7 6 8 12 14
2 5 4 9 15 11
*/

Compilation message (stderr)

building4.cpp: In function 'int main()':
building4.cpp:76:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |  freopen("01-11.txt","r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 11
• Subtask 2: 0 / 89