【AC自动机+数位DP】SDOI2014 数数

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【SDOI2014】数数

【题目大意】

#include<cstdio>#include<cstring>#include<algorithm>#define fo(i,a,b) for (int i = a;i <= b;i ++)using namespace std;const int maxn = 1505;const int P = (int)1e9 + 7;int N[maxn],M,S[maxn],tot;void read(int *x){x[0] = 0;static char ch;do ch = getchar(); while (ch < '0' || ch > '9');do x[++x[0]] = ch - 48, ch = getchar(); while (ch >= '0' && ch <= '9');}struct Node{int son[10],fail;bool flag;}t[maxn];void Insert(int *s){int x = 0;fo(i,1,s[0]){if (!t[x].son[s[i]]) t[x].son[s[i]] = ++ tot;x = t[x].son[s[i]];}t[x].flag = 1;}void Construct_fail(){static int d[maxn];int l = 0,r = 1;while (l < r){int x = d[++l];fo(i,0,9)if (t[x].son[i]){int v = t[x].son[i];if (x == 0) t[v].fail = 0;else t[v].fail = t[t[x].fail].son[i];t[v].flag |= t[t[v].fail].flag;d[++r] = v;} else t[x].son[i] = t[t[x].fail].son[i];}}void Initialize(){read(N);scanf("%d",&M);fo(i,1,M){read(S);Insert(S);}Construct_fail();}int f[maxn][maxn][2];int DP(){fo(i,1,N[1]-1) if (!t[t[0].son[i]].flag) f[1][t[0].son[i]][0] ++;if (!t[t[0].son[N[1]]].flag) f[1][t[0].son[N[1]]][1] ++;fo(i,1,N[0]){if (i > 1)fo(j,1,9) if (!t[t[0].son[j]].flag) f[i][t[0].son[j]][0] ++;fo(j,0,tot){if (f[i][j][0])fo(k,0,9){int _j = t[j].son[k];if (!t[_j].flag) f[i+1][_j][0] = (f[i+1][_j][0] + f[i][j][0]) % P;}if (f[i][j][1]){fo(k,0,N[i+1]-1){int _j = t[j].son[k];if (!t[_j].flag) f[i+1][_j][0] = (f[i+1][_j][0] + f[i][j][1]) % P;}int _j = t[j].son[N[i+1]];if (!t[_j].flag) f[i+1][_j][1] = (f[i+1][_j][1] + f[i][j][1]) % P;}}}int ret = 0;fo(i,0,tot) ret = ((ret + f[N[0]][i][0]) % P + f[N[0]][i][1]) % P;return ret;}int main(){freopen("count.in","r",stdin);freopen("count.out","w",stdout);Initialize();printf("%d\n",DP());return 0;}

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