Submission #262991

#	Time	Username	Problem	Language	Result	Execution time	Memory
262991		amiratou	Linear Garden (IOI08_linear_garden)	C++14	100 / 100	560 ms	10268 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[2][16][5],state[MX],comp[MX];

int32_t main(){
	boost;
	//freopen(".in","r",stdin);
	cin>>n>>m>>S;
	for (int mask = 0; mask < 16; ++mask)
		for (int cnt = 0; cnt < 5; ++cnt)
			dp[n&1][mask][cnt]=1;
	int ans=0,C=0,curr=0;
	for (int i = 0; i < n; ++i){
		C+=((S[i]=='P')?-1:1);
		if(C==-1)curr|=(1<<2);
		else if(C==1)curr|=(1<<1);
		else if(C==2)curr|=(1<<0);
		else if(C==-2)curr|=(1<<3);
		state[i]=curr;
		comp[i]=C;
	}
	for (int idx = n-1; idx >= 0; idx--)
	{
		int k=(idx?comp[idx-1]:0);
		curr=(idx?state[idx-1]:0);
		if((S[idx]=='P') && ((k+1)<=2)){
			k++;
			if((k==2) && !(((curr>>2)&1)|((curr>>3)&1)))ans=(ans+dp[(idx+1)&1][curr|(1<<0)][k+2])%m;
			if((k==1) && !((curr>>3)&1))ans=(ans+dp[(idx+1)&1][curr|(1<<1)][k+2])%m;
			if(k==0)ans=(ans+dp[(idx+1)&1][curr][k+2])%m;
			if((k==-1) && !((curr>>0)&1))ans=(ans+dp[(idx+1)&1][curr|(1<<2)][k+2])%m;
			if((k==-2) && !(((curr>>0)&1)|((curr>>1)&1)))ans=(ans+dp[(idx+1)&1][curr|(1<<3)][k+2])%m;
			k--;
		}
		for (int mask = 0; mask < 16; ++mask){
			for (int cnt = 0; cnt < 5; ++cnt)
			{
				int h=cnt-2;
				if((h+1) <=2){
					h++;
					if((h==2) && !(((mask>>2)&1)|((mask>>3)&1)))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<0)][h+2])%m;
					if((h==1) && !((mask>>3)&1))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<1)][h+2])%m;
					if(h==0)dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask][h+2])%m;
					if((h==-1) && !((mask>>0)&1))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<2)][h+2])%m;
					if((h==-2) && !(((mask>>0)&1)|((mask>>1)&1)))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<3)][h+2])%m;
					h--;
				}
				if((h-1) >=-2){
					h--;
					if((h==2) && !(((mask>>2)&1)|((mask>>3)&1)))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<0)][h+2])%m;
					if((h==1) && !((mask>>3)&1))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<1)][h+2])%m;
					if(h==0)dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask][h+2])%m;
					if((h==-1) && !((mask>>0)&1))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<2)][h+2])%m;
					if((h==-2) && !(((mask>>0)&1)|((mask>>1)&1)))dp[idx&1][mask][cnt]=(dp[idx&1][mask][cnt]+dp[(idx+1)&1][mask|(1<<3)][h+2])%m;
					h++;
				}
			}
		}
		for (int mask = 0; mask < 16; ++mask)
			for (int cnt = 0; cnt < 5; ++cnt)dp[(idx+1)&1][mask][cnt]=0;
	}
	cout<<(ans+1)%m<<"\n";
	return 0;
}

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

• Subtask 1: 2 / 2
• Subtask 2: 2 / 2
• Subtask 3: 4 / 4
• Subtask 4: 4 / 4
• Subtask 5: 4 / 4
• Subtask 6: 4 / 4
• Subtask 7: 4 / 4
• Subtask 8: 4 / 4
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• Subtask 11: 4 / 4
• Subtask 12: 5 / 5
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• Subtask 14: 5 / 5
• Subtask 15: 5 / 5
• Subtask 16: 5 / 5
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• Subtask 18: 5 / 5
• Subtask 19: 5 / 5
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• Subtask 22: 5 / 5
• Subtask 23: 5 / 5