Submission #959695

#	Time	Username	Problem	Language	Result	Execution time	Memory
959695		MilosMilutinovic	Cheerleaders (info1cup20_cheerleaders)	C++14	62 / 100	1265 ms	2508 KiB

cheerleaders

#include<bits/stdc++.h>
 
#define pb push_back
#define fi first
#define se second
#define mp make_pair
 
using namespace std;
 
typedef long long ll;
typedef unsigned long long ull;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;
typedef long double ld;
 
template <typename T> bool chkmin(T &x,T y){return x>y?x=y,1:0;}
template <typename T> bool chkmax(T &x,T y){return x<y?x=y,1:0;}
 
ll readint(){
	ll x=0,f=1; char ch=getchar();
	while(ch<'0'||ch>'9'){if(ch=='-')f=-1;ch=getchar();}
	while(ch>='0'&&ch<='9'){x=x*10+ch-'0';ch=getchar();}
	return x*f;
}

int n;
int h[1<<20],cnt[1<<20],a[1<<20],b[1<<20];
string str;

int ask(int p){
	int ret=0;
	while(p>=0){
		ret+=cnt[p];
		p=(p&(p+1))-1;
	}
	return ret;
}

void change(int p,int v){
	while(p<(1<<n)){
		cnt[p]+=v;
		p|=(p+1);
	}
}

ll solve(){
	for(int i=0;i<(1<<n);i++) cnt[i]=0;
	ll ret=0;
	for(int i=(1<<n)-1;i>=0;i--){
		ret+=ask(h[i]);
		change(h[i],1);
	}
	return ret;
}

void op2(){
	int x=0,y=0;
	for(int i=0;i<(1<<n);i++){
		if(i%2==0) a[x]=h[i],x++;
		if(i%2==1) b[y]=h[i],y++;
	}
	int p=0,q=0;
	for(int i=0;i<(1<<n);i++){
		if(p<x) h[i]=a[p],p++;
		else h[i]=b[q],q++;
	}
}

ll work(int x){
	for(int iter=0;iter<x;iter++) op2();
	int msk=0;
	ll ret=solve();
	str="";
	for(int i=0;i<x;i++) str+='2';
	for(int i=0;i<n;i++){
		for(int j=0;j<(1<<n);j++) b[j]=h[j];
		for(int j=0;j<(1<<n);j++) a[j^(1<<i)]=h[j];
		for(int j=0;j<(1<<n);j++) h[j]=a[j];
		ll cur=solve();
		if(cur<ret){
			ret=cur;
			msk^=(1<<i);
		}else{
			for(int j=0;j<(1<<n);j++) h[j]=b[j];
		}
	}
	for(int i=n-1;i>=0;i--){
		if(msk>>i&1) str+='1';
		str+='2';
	}
	for(int i=0;i<n;i++){
		if(!(msk>>i&1)) continue;
		for(int j=0;j<(1<<n);j++) a[j^(1<<i)]=h[j];
		for(int j=0;j<(1<<n);j++) h[j]=a[j];
	}
	for(int iter=0;iter<n-x;iter++) op2();
	return ret;
}

int main(){
	n=readint();
	for(int i=0;i<(1<<n);i++) h[i]=readint();
	ll res=work(0);
	int bst=0;
	for(int i=1;i<n;i++){
		ll c=work(i);
		if(c<res) res=c,bst=i;
	}
	work(bst);
	printf("%lld\n",res);
	for(char c:str) printf("%c",c);
	return 0;
}

• Subtask 1: 16 / 16
• Subtask 2: 5 / 10
• Subtask 3: 20 / 25
• Subtask 4: 0 / 21
• Subtask 5: 21 / 28