# | Time | Username | Problem | Language | Result | Execution time | Memory |
---|---|---|---|---|---|---|---|
238576 | vankata | Trener (COCI20_trener) | C++14 | 0 ms | 0 KiB |
This submission is migrated from previous version of oj.uz, which used different machine for grading. This submission may have different result if resubmitted.
#include<bits/stdc++.h>
using namespace std;
struct tri
{
int x,y,z;
tri() {};
tri(int a,int b,int c)
{
x=a;
y=b;
z=c;
}
bool operator <(const tri &t)const
{
if(t.x==x)
{
if(t.y==y)
{
return z<t.z;
}
return y<t.y;
}
return x<t.x;
}
bool operator ==(const tri &t)const
{
return t.x==x&&t.y==y&&t.z==z;
}
};
const long long MAXN = 2048;
const long long MOD = (long long )(1e9+7);
tri h[64][MAXN];
long long dp[64][MAXN];
tri hsh(string s)
{
int l,i;
long long base[3]= {29,31,37};
long long mod[3]= {1e7+7,1e9+7,1e9+9};
long long h1[3]= {0,0,0};
for(i=0; i<s.size(); i++)
{
for(l=0; l<3; l++)
{
h1[l]*=base[l];
h1[l]+=(s[i]-'a'+1);
h1[l]%=mod[l];
}
}
return {h1[0],h1[1],h1[2]};
}
vector<string>v[64];
long long n,k;
void solve()
{
int i,j,l;
tri t1,t2;
string t,q;
for(i=0; i<k; i++)dp[0][i]=1;
for(i=1; i<n; i++)
{
for(j=0; j<k; j++)
{
t=v[i][j].substr(0,i);
q=v[i][j].substr(1);
t1=hsh(t);
t2=hsh(q);
for(l=0; l<k; l++)
{
if(h[i-1][l]==t1||h[i-1][l]==t2)
{
dp[i][j]+=dp[i-1][l];
dp[i][j]%=MOD;
}
}
}
}
long long ans = 0;
for(i=0; i<k; i++)
{
ans+=dp[n-1][i];
ans%=MOD;
}
cout<<ans<<"\n";
}
void read()
{
int i,j;
string s;
cin>>n>>k;
for(i=0; i<n; i++)
{
for(j=0; j<k; j++)
{
cin>>s;
v[i].push_back(s);
h[i][j]=hsh(s);
}
}
}
int main()
{
ios_base::sync_with_stdio(0);
cin.tie(0);
cout.tie(0);
read();
solve();
return 0;
}