Submission #143654

#	Time	Username	Problem	Language	Result	Execution time	Memory
143654		vladciuperceanu	Mate (COCI18_mate)	C++14	100 / 100	546 ms	56824 KiB

mate

#include <cstdio>
#include <cstring>
#define MOD 1000000007

using namespace std;

long long Q,d,i,j,comb[2005][2005],D[2005][30][30];
long long r[2005][30],poz[30][2005],sol[2005][30][30];
char s[2005],x,y;

int main()
{
    scanf("%s", (s+1));
    int n = strlen((s+1));
    comb[0][0] = 1;
    for (i=1; i<=n; i++)
    {
        comb[i][0] = comb[i][i] = 1;
        for (j=1; j<i; j++)
        {
            comb[i][j] = comb[i-1][j-1]+comb[i-1][j];
            if (comb[i][j] >= MOD)
                comb[i][j] -= MOD;
        }
    }
    for (i=1; i<=n; i++)
        poz[s[i]-'a'][++poz[s[i]-'a'][0]] = i;
    for (i=n; i>=1; i--)
        for (j=0; j<26; j++)
            if (s[i] == 'a'+j)
                r[i][j] = 1+r[i+1][j];
            else
                r[i][j] = r[i+1][j];
    for (i=n; i>=1; i--)
        for (j=0; j<26; j++)
            for (int k=0; k<26; k++)
                if (s[i] == 'a'+j)
                    D[i][j][k] = r[i+1][k];
                else
                    D[i][j][k] = D[i+1][j][k];
    for (int l=2; l<=n; l++)
        for (j=0; j<26; j++)
            for (int t=1; t<=poz[j][0]; t++)
            {
                i = poz[j][t];
                if (i >= l-1)
                    for (int k=0; k<26; k++)
                    {
                        sol[l][j][k] += (D[i][j][k]*comb[i-1][l-2])%MOD;
                        if (sol[l][j][k] >= MOD)
                            sol[l][j][k] -= MOD;
                    }
            }
    scanf("%lld", &Q);
    for (;Q--;)
    {
        scanf("%lld %c %c", &d, &x, &y);
        printf("%lld\n", sol[d][x-'a'][y-'a']);
    }
    return 0;
}

Compilation message (stderr)

mate.cpp: In function 'int main()':
mate.cpp:13:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%s", (s+1));
     ~~~~~^~~~~~~~~~~~~
mate.cpp:54:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%lld", &Q);
     ~~~~~^~~~~~~~~~~~
mate.cpp:57:14: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
         scanf("%lld %c %c", &d, &x, &y);
         ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 100 / 100