Submission #262944

#	Time	Username	Problem	Language	Result	Execution time	Memory
262944		amiratou	Linear Garden (IOI08_linear_garden)	C++14	0 / 100	54 ms	65540 KiB

linear_garden

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
using namespace std;
#define boost ios_base::sync_with_stdio(false); cin.tie(0); cout.tie(0)
#define rando mt19937 rng(chrono::steady_clock::now().time_since_epoch().count())
#define fi first
#define se second
#define debug(x) cerr << " - " << #x << ": " << x << endl;
#define debugs(x, y) cerr << " - " << #x << ": " << x << " " << #y << ": " << y << endl;
#define debugii(x) cerr << " - " << #x << ": " << x.fi<<","<<x.se << endl;
#define sep() cerr << "--------------------" << endl;
#define all(x) (x).begin(),(x).end()
#define sz(x) (ll)x.size()
#define ld long double
#define ll long long
//#define int ll
#define ii pair<int,int>
#define v vector<int>
#define vii vector<ii>
#define vv vector<vector<int> >
#define mp make_pair
#define INF 1000000000
#define pb push_back
#define EPS 1e-9
const int MOD = 1000000007; // 998244353
const int MX = 1000001;
string S;
int n,m,dp[MX][16][5];
int solve(int idx,int mask,int cnt){
	if(idx==n)return 1;
	if(dp[idx][mask][cnt]!=-1)
		return dp[idx][mask][cnt];
	int h=cnt-2,ans=0;
	if((h+1) <=2){
		h++;
		if((h==2) && !(((mask>>2)&1)|((mask>>3)&1)))ans=(ans+solve(idx+1,mask|(1<<0),h+2))%m;
		if((h==1) && !((mask>>3)&1))ans=(ans+solve(idx+1,mask|(1<<1),h+2))%m;
		if(h==0)ans=(ans+solve(idx+1,mask,h+2))%m;
		if((h==-1) && !((mask>>0)&1))ans=(ans+solve(idx+1,mask|(1<<2),h+2))%m;
		if((h==-2) && !(((mask>>0)&1)|((mask>>1)&1)))ans=(ans+solve(idx+1,mask|(1<<3),h+2))%m;
		h--;
	}
	if((h-1) >=-2){
		h--;
		if((h==2) && !(((mask>>2)&1)|((mask>>3)&1)))ans=(ans+solve(idx+1,mask|(1<<0),h+2))%m;
		if((h==1) && !((mask>>3)&1))ans=(ans+solve(idx+1,mask|(1<<1),h+2))%m;
		if(h==0)ans=(ans+solve(idx+1,mask,h+2))%m;
		if((h==-1) && !((mask>>0)&1))ans=(ans+solve(idx+1,mask|(1<<2),h+2))%m;
		if((h==-2) && !(((mask>>0)&1)|((mask>>1)&1)))ans=(ans+solve(idx+1,mask|(1<<3),h+2))%m;
		h++;
	}
	return dp[idx][mask][cnt]=ans;
}

int32_t main(){
	boost;
	//freopen(".in","r",stdin);
	memset(dp,-1,sizeof dp);
	cin>>n>>m>>S;
	int ans=0,cnt=0,mask=0;
	for (int i = 0; i < n; ++i){
		if((S[i]=='P') && ((cnt+1)<=2)){
			cnt++;
			if((cnt==2) && !(((mask>>2)&1)|((mask>>3)&1)))ans=(ans+solve(i+1,mask|(1<<0),cnt+2))%m;
			if((cnt==1) && !((mask>>3)&1))ans=(ans+solve(i+1,mask|(1<<1),cnt+2))%m;
			if(cnt==0)ans=(ans+solve(i+1,mask,cnt+2))%m;
			if((cnt==-1) && !((mask>>0)&1))ans=(ans+solve(i+1,mask|(1<<2),cnt+2))%m;
			if((cnt==-2) && !(((mask>>0)&1)|((mask>>1)&1)))ans=(ans+solve(i+1,mask|(1<<3),cnt+2))%m;
			cnt--;
		}
		cnt+=((S[i]=='P')?-1:1);
		if(cnt==-1)mask|=(1<<2);
		else if(cnt==1)mask|=(1<<1);
		else if(cnt==2)mask|=(1<<0);
		else if(cnt==-2)mask|=(1<<3);
	}
	cout<<(ans+1)%m<<"\n";
	return 0;
}

//do smth instead of nothing and stay organized
//long long
//array bounds
//special cases
//binary search

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