CSES - Putka Open 2025 – 4/5

Submission details
Task:	Merkkijonot
Sender:	Sisuaski
Submission time:	2025-11-09 20:58:38 +0200
Language:	C++ (C++20)
Status:	READY
Result:	18

Feedback
group	verdict	score
#1	ACCEPTED	18
#2	TIME LIMIT EXCEEDED	0
#3	TIME LIMIT EXCEEDED	0
#4	TIME LIMIT EXCEEDED	0
#5	TIME LIMIT EXCEEDED	0

Test results
test	verdict	time	group
#1	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#2	ACCEPTED	0.14 s	2, 3, 4, 5	details
#3	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#4	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#5	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#6	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#7	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#8	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#9	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#10	ACCEPTED	0.02 s	1, 2, 3, 4, 5	details
#11	ACCEPTED	0.02 s	2, 3, 4, 5	details
#12	ACCEPTED	0.02 s	2, 3, 4, 5	details
#13	TIME LIMIT EXCEEDED	--	2, 3, 4, 5	details
#14	RUNTIME ERROR	0.04 s	2, 3, 4, 5	details
#15	ACCEPTED	0.02 s	2, 3, 4, 5	details
#16	ACCEPTED	0.05 s	2, 3, 4, 5	details
#17	ACCEPTED	0.03 s	2, 3, 4, 5	details
#18	ACCEPTED	0.02 s	2, 3, 4, 5	details
#19	ACCEPTED	0.03 s	3, 4, 5	details
#20	TIME LIMIT EXCEEDED	--	3, 4, 5	details
#21	TIME LIMIT EXCEEDED	--	3, 4, 5	details
#22	RUNTIME ERROR	0.04 s	3, 4, 5	details
#23	ACCEPTED	0.02 s	3, 4, 5	details
#24	ACCEPTED	0.06 s	3, 4, 5	details
#25	ACCEPTED	0.03 s	3, 4, 5	details
#26	ACCEPTED	0.03 s	3, 4, 5	details
#27	ACCEPTED	0.04 s	4, 5	details
#28	ACCEPTED	0.04 s	4, 5	details
#29	TIME LIMIT EXCEEDED	--	4, 5	details
#30	RUNTIME ERROR	0.04 s	4, 5	details
#31	ACCEPTED	0.02 s	4, 5	details
#32	ACCEPTED	0.09 s	4, 5	details
#33	ACCEPTED	0.04 s	4, 5	details
#34	ACCEPTED	0.03 s	4, 5	details
#35	ACCEPTED	0.04 s	5	details
#36	ACCEPTED	0.13 s	5	details
#37	TIME LIMIT EXCEEDED	--	5	details
#38	RUNTIME ERROR	0.04 s	5	details
#39	ACCEPTED	0.03 s	5	details
#40	ACCEPTED	0.12 s	5	details
#41	ACCEPTED	0.05 s	5	details
#42	ACCEPTED	0.04 s	5	details

Code

#include <iostream>
#include <cstring>
#include <vector>
#include <algorithm>
#include <unordered_map>
using namespace std;
typedef long long ll;

const int Z = 1e9+7;
const int A = 'z'-'a'+1;
struct Node {
	int cs[A];
};
Node nodes[10240];
int C;

struct NN {
	vector<int> out;
	int type;
	int par;

	bool operator==(const NN& n) const {
		if (type != n.type) return 0;
		if (out.size() != n.out.size()) return 0;
		for(size_t i=0; i<out.size(); ++i) if (out[i]!=n.out[i]) return 0;
		return 1;
	}
};
NN nns[10240];
int newIdx[10240];

struct NNH {
	size_t operator()(const NN& n) const {
		size_t h=n.type;
		for(size_t i=0; i<n.out.size(); ++i) {
			h = h*3333331 + n.out[i];
		}
		return h;
	}
};

int getP(int i) {
	if (nns[i].par==i) return i;
	return nns[i].par = getP(nns[i].par);
}
void normalize(int i) {
	NN& n = nns[i];
	for(int& x: n.out) {
		x = getP(x);
	}
	sort(n.out.begin(),n.out.end());
}

struct Mat {
	static const int MS = 1000;
	int a[MS][MS];

	const int* operator[](int i)const{return a[i];}
	int* operator[](int i){return a[i];}
};

Mat operator*(const Mat& a, const Mat& b) {
	Mat m;
	for(int i=0; i<C; ++i) {
		for(int j=0; j<C; ++j) {
			ll r=0;
			for(int k=0; k<C; ++k) {
				r += (ll)a[i][k] * b[k][j] % Z;
			}
			m[i][j] = r % Z;
		}
	}
	return m;
}
Mat mpow(Mat m, int e) {
#if 0
	if (e==1) return m;
	Mat r = mpow(m*m,e/2);
	return e&1 ? r*m : r;
#else
	Mat res={};
	for(int i=0; i<C; ++i) res[i][i]=1;
	for(int i=1; i<=e; i*=2, m=m*m) {
		if (e&i) res = res*m;
	}
	return res;
#endif
}

string s;

void addPrefix(int ci, string cur) {
	Node& c = nodes[ci];
	cur.push_back(0);
	for(int i=0; i<A; ++i) {
		cur[cur.size()-1]='a'+i;
		if (c.cs[i]<0) {
			string x = cur;
			while(x != s.substr(0,x.size())) x = x.substr(1);
			if (!x.empty()) {
				c.cs[i] = x.size();
			}
		} else if (c.cs[i]>ci) {
			addPrefix(c.cs[i], cur);
		}
	}
}

int main() {
	int n,m;
	cin>>n>>m>>s;

	memset(nodes,-1,sizeof(nodes));

	for(int k=0; k<m; ++k) {
		for(char c='a'; c<='z'; ++c) {
			string cur = s.substr(0,k) + c;
			int x=cur.size();
			for(;x>0 && s.substr(0,x)!=cur.substr(cur.size()-x);x--);
			if (!x) continue;
			nodes[k].cs[c-'a'] = x;
		}
	}
	C = m+1;

	for(int k=m-1; k>=0; --k) {
		int ci = m;
		for(int j=k; j<m; ++j) {
			int x = s[j]-'a';
			Node& c = nodes[ci];
			if (j+1<m) {
				if (c.cs[x]<0) c.cs[x] = C++;
				ci = c.cs[x];
			} else c.cs[x] = m;
			if (ci==1) break;
		}
	}
	addPrefix(m, "");

	for(int i=0; i<C; ++i) {
		nns[i].type = i==0 ? 0 : i==m ? 1 : 2;
		nns[i].par=i;
		for(int j=0; j<A; ++j) {
			int t = nodes[i].cs[j];
			if (t<0) continue;
			nns[i].out.push_back(t);
		}
	}
	bool doMerge = 0;
	while(doMerge) {
		doMerge = 0;
		unordered_map<NN,int,NNH> nmap;
		for(int i=0; i<C; ++i) {
			auto it = nmap.find(nns[i]);
			if (it == nmap.end()) {
				nmap[nns[i]] = i;
			} else {
				nns[i].par = it->second;
				doMerge = 1;
			}
		}

		for(int i=0; i<C; ++i) {
			normalize(i);
		}

		int cc=0;
		for(int i=0; i<C; ++i) {
			if (nns[i].par != i) continue;
			newIdx[i] = cc;
			nns[cc] = nns[i];
			nns[cc].par = cc;
			cc++;
		}
		C = cc;

		for(int i=0; i<C; ++i) {
			for(int& x: nns[i].out) x = newIdx[x];
		}
	}

	int st=0,ed=0;
	for(int i=0; i<C; ++i) {
		if (nns[i].type==0) st=i;
		if (nns[i].type==1) ed=i;
	}

	Mat mat={};
	for(int i=0; i<C; ++i) {
		for(int t: nns[i].out) mat[i][t]++;
	}
	Mat res = mpow(mat,n);
	cout<<res[st][ed]<<'\n';
}

Test details

Test 1

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`1 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 2

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 20 ssxfykmuzljmwgyvldnu` view save

correct output
`1` view save

user output
`1` view save

Test 3

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 aaaaaaaaaa` view save

correct output
`1` view save

user output
`1` view save

Test 4

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 aabbbaaaab` view save

correct output
`1532` view save

user output
`1532` view save

Test 5

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 aabbacbdca` view save

correct output
`1542` view save

user output
`1542` view save

Test 6

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 ztknszhrby` view save

correct output
`3261` view save

user output
`3261` view save

Test 7

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 8

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 aabbbbbbba` view save

correct output
`1689` view save

user output
`1689` view save

Test 9

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 8 abxabyab` view save

correct output
`8619` view save

user output
`8619` view save

Test 10

Group: 1, 2, 3, 4, 5

Verdict: ACCEPTED

input
`20 10 ababababab` view save

correct output
`509` view save

user output
`509` view save

Test 11

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 50 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...` view save

correct output
`1` view save

user output
`1` view save

Test 12

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 50 bbaaabbbbbabbbbabababababbbaab...` view save

correct output
`511493117` view save

user output
`511493117` view save

Test 13

Group: 2, 3, 4, 5

Verdict: TIME LIMIT EXCEEDED

input
`100 50 addabbbbbadddccadcabaacbbbaabd...` view save

correct output
`618572722` view save

user output
(empty)

Test 14

Group: 2, 3, 4, 5

Verdict: RUNTIME ERROR

input
`100 50 rrdumiqrjewanjplbyvkaytbcyzbyl...` view save

correct output
`35126431` view save

user output
(empty)

Test 15

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 16

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 50 aabbbbbbbbbbbbbbbbbbbbbbbbbbbb...` view save

correct output
`460606355` view save

user output
`460606355` view save

Test 17

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 23 aybabtuxaybabtuyaybabtu` view save

correct output
`342213037` view save

user output
`342213037` view save

Test 18

Group: 2, 3, 4, 5

Verdict: ACCEPTED

input
`100 50 ababababababababababababababab...` view save

correct output
`775006564` view save

user output
`775006564` view save

Test 19

Group: 3, 4, 5

Verdict: ACCEPTED

input
`1000 50 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...` view save

correct output
`1` view save

user output
`1` view save

Test 20

Group: 3, 4, 5

Verdict: TIME LIMIT EXCEEDED

input
`1000 50 bbabaabbabbbaaaaaaaaaababaabbb...` view save

correct output
`911592620` view save

user output
(empty)

Test 21

Group: 3, 4, 5

Verdict: TIME LIMIT EXCEEDED

input
`1000 50 cacabdddcbdadabdcbdddbdddbaccb...` view save

correct output
`12869296` view save

user output
(empty)

Test 22

Group: 3, 4, 5

Verdict: RUNTIME ERROR

input
`1000 50 tqoyadbshyehwcwaxbtbsqtaswkyet...` view save

correct output
`741984969` view save

user output
(empty)

Test 23

Group: 3, 4, 5

Verdict: ACCEPTED

input
`1000 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 24

Group: 3, 4, 5

Verdict: ACCEPTED

input
`1000 50 aabbbbbbbbbbbbbbbbbbbbbbbbbbbb...` view save

correct output
`599950419` view save

user output
`599950419` view save

Test 25

Group: 3, 4, 5

Verdict: ACCEPTED

input
`1000 23 aybabtuxaybabtuyaybabtu` view save

correct output
`548809016` view save

user output
`548809016` view save

Test 26

Group: 3, 4, 5

Verdict: ACCEPTED

input
`1000 50 ababababababababababababababab...` view save

correct output
`765799780` view save

user output
`765799780` view save

Test 27

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 50 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...` view save

correct output
`1` view save

user output
`1` view save

Test 28

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 50 bbaababbaaabbabababbaaaaaabbaa...` view save

correct output
`514073453` view save

user output
`514073453` view save

Test 29

Group: 4, 5

Verdict: TIME LIMIT EXCEEDED

input
`1000000 50 aabccabbbbabccabcdcdadbcdccdac...` view save

correct output
`438094288` view save

user output
(empty)

Test 30

Group: 4, 5

Verdict: RUNTIME ERROR

input
`1000000 50 yzfzimxrxfukhlkrtaylohyuqkupsn...` view save

correct output
`905445077` view save

user output
(empty)

Test 31

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 32

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 50 aabbbbbbbbbbbbbbbbbbbbbbbbbbbb...` view save

correct output
`280596224` view save

user output
`280596224` view save

Test 33

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 23 aybabtuxaybabtuyaybabtu` view save

correct output
`268144314` view save

user output
`268144314` view save

Test 34

Group: 4, 5

Verdict: ACCEPTED

input
`1000000 50 ababababababababababababababab...` view save

correct output
`655244665` view save

user output
`655244665` view save

Test 35

Group: 5

Verdict: ACCEPTED

input
`1000000000 50 aaaaaaaaaaaaaaaaaaaaaaaaaaaaaa...` view save

correct output
`1` view save

user output
`1` view save

Test 36

Group: 5

Verdict: ACCEPTED

input
`1000000000 50 abbbaabbaaaaabbbbabbabbaaaaaba...` view save

correct output
`911059863` view save

user output
`911059863` view save

Test 37

Group: 5

Verdict: TIME LIMIT EXCEEDED

input
`1000000000 50 cbabbcaadabbcabbdbdabbbcccbdca...` view save

correct output
`994268014` view save

user output
(empty)

Test 38

Group: 5

Verdict: RUNTIME ERROR

input
`1000000000 50 pehyicejeninplaczwezhahmbhwfwi...` view save

correct output
`837165971` view save

user output
(empty)

Test 39

Group: 5

Verdict: ACCEPTED

input
`1000000000 1 a` view save

correct output
`1` view save

user output
`1` view save

Test 40

Group: 5

Verdict: ACCEPTED

input
`1000000000 50 aabbbbbbbbbbbbbbbbbbbbbbbbbbbb...` view save

correct output
`114333489` view save

user output
`114333489` view save

Test 41

Group: 5

Verdict: ACCEPTED

input
`1000000000 23 aybabtuxaybabtuyaybabtu` view save

correct output
`628064772` view save

user output
`628064772` view save

Test 42

Group: 5

Verdict: ACCEPTED

input
`1000000000 50 ababababababababababababababab...` view save

correct output
`802946327` view save

user output
`802946327` view save

Putka Open 2025 – 4/5

Merkkijonot

Code

Test details

Test 1

Test 2

Test 3

Test 4

Test 5

Test 6

Test 7

Test 8

Test 9

Test 10

Test 11

Test 12

Test 13

Test 14

Test 15

Test 16

Test 17

Test 18

Test 19

Test 20

Test 21

Test 22

Test 23

Test 24

Test 25

Test 26

Test 27

Test 28

Test 29

Test 30

Test 31

Test 32

Test 33

Test 34

Test 35

Test 36

Test 37

Test 38

Test 39

Test 40

Test 41

Test 42

Tasks

Submissions (Sisuaski)