Codeforces621E 矩阵构造快速幂

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比赛的时候构造矩阵想岔了，矩阵构造熟练度明显不够。。。
ACCode：
#pragma comment(linker, "/STACK:1024000000,1024000000")#include<cstdio>#include<cstring>#include<algorithm>#include<iostream>#include<vector>#include<set>#include<map>#include<queue>#include<sstream>#include<string>#include<bitset>using namespace std;typedef long long LL;const LL LINF = (1LL <<63);const int INF = 1 << 31;const int NS = 100010;const int MS = 10;const int KS = 105;const LL MOD = 1000000007;struct matrix{    #define M_SIZE (KS)    int len;    int a[M_SIZE][M_SIZE];    void initClear(int _len)    {        len = _len;        memset(a, 0, sizeof(a));    }    void initOne(int _len)    {        initClear(_len);        for(int i = 0; i < len; i++)        {            a[i][i] = 1;        }    }    void initStruct(int _len, int* dig)    {        initClear(_len);        int lim = min(MS, len);        for(int i = 0; i < len; i++)        {            for(int j = 0; j < lim; j++)            {                int vi = (i * 10 + j) % len;                a[i][vi] += dig[j];            }        }    }    matrix operator * (const matrix &right)const    {        matrix res; res.initClear(len);        for(int row = 0; row < len; row++)        {            for(int col = 0; col < len; col++)            {                for(int pos = 0; pos < len; pos++)                {                    if(a[row][pos] > 0 && right.a[pos][col])                    {                        res.a[row][col] += ((LL)a[row][pos] * right.a[pos][col]) % MOD;                        if(res.a[row][col] >= MOD)                        {                            res.a[row][col] -= MOD;                        }                    }                }            }        }        return res;    }    matrix operator + (const matrix &right)const    {        matrix res; res.initClear(len);        for(int row = 0; row < len; row++)        {            for(int col = 0; col < len; col++)            {                res.a[row][col] = (this->a[row][col] + right.a[row][col]);                if(res.a[row][col] >= MOD)                {                    res.a[row][col] -= MOD;                }                else if(res.a[row][col] < 0)                {                    res.a[row][col] += MOD;                }            }        }        return res;    }    matrix qpow(LL y)    {        matrix ans; ans.initOne(this->len);        matrix x; x = *this;        for(;y > 0; y >>= 1)        {            if(y & 1)            {                ans = ans * x;            }            x = x * x;        }        return ans;    }    void print()    {        for(int row = 0; row < len; row++)        {            for(int col = 0; col < len; col++)            {                cout<<this->a[row][col]<<" ";            }            puts("");        }        puts("");    }};int n, b, k, x;int dig[MS];matrix mat;int main(){#ifndef ONLINE_JUDGE    freopen("621E.in", "r", stdin);//    freopen("out.txt", "w", stdout);#endif    while(~scanf("%d %d %d %d", &n, &b, &k, &x))    {        int d;        memset(dig, 0, sizeof(dig));        for(int i = 0; i < n; i++)        {            scanf("%d", &d);            dig[d]++;        }        if(x < MS)        {            for(int i = x; i < MS; i++)            {                dig[i % x] += dig[i];                dig[i] = 0;            }        }        mat.initStruct(x, dig);//        mat.print();//        printf("-------------\n");        mat = mat.qpow(b);//        mat.print();//        printf("-------------\n");        printf("%d\n", mat.a[0][k]);    }    return 0;}
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