题目大意:给定N,M,K,然后给定一个N字符的字符集和,现在要用这些字符组成一个长度为M的字符串,要求不包
括K个子字符串。
解题思路:AC自动机+DP+高精度。这题恶心的要死,给定的不能匹配字符串里面有负数的字符情况,也算是涨姿势
了,对应每个字符固定偏移128单位。
#include <cstdio>
#include <cstring>
#include <queue>
#include <vector>
#include <iostream>
#include <algorithm>
using namespace std;
typedef long long ll;
const int maxn = 505;
const int sigma_size = 256;
const int bw = 128;
struct Aho_Corasick {
int sz, g[maxn][sigma_size];
int tag[maxn], fail[maxn], last[maxn];
void init();
int idx(char ch);
void insert(char* str, int k);
void getFail();
void match(char* str);
void put(int x, int y);
}A;
struct bign {
int len, num[100];
bign () {
len = 0;
memset(num, 0, sizeof(num));
}
bign (int number) {*this = number;}
bign (const char* number) {*this = number;}
void delzero ();
void Put ();
void operator = (int number);
void operator = (char* number);
bool operator < (const bign& b) const;
bool operator > (const bign& b) const { return b < *this; }
bool operator <= (const bign& b) const { return !(b < *this); }
bool operator >= (const bign& b) const { return !(*this < b); }
bool operator != (const bign& b) const { return b < *this || *this < b;}
bool operator == (const bign& b) const { return !(b != *this); }
void operator ++ ();
void operator -- ();
bign operator + (const int& b);
bign operator + (const bign& b);
bign operator - (const int& b);
bign operator - (const bign& b);
bign operator * (const int& b);
bign operator * (const bign& b);
bign operator / (const int& b);
int operator % (const int& b);
}dp[2][maxn];
int N, M, K, tab[55];
char s[55];
void solve() {
int n = A.sz;
for (int i = 0; i < n; i++)
dp[0][i] = 0;
dp[0][0] = 1;
for (int i = 0; i < M; i++) {
int now = i&1, nxt = !(i&1);
for (int i = 0; i < n; i++) dp[nxt][i] = 0;
for (int i = 0; i < n; i++) {
if (A.tag[i] || A.last[i])
continue;
for (int j = 0; j < N; j++) {
int v = tab[j], u = i;
while (u && A.g[u][v] == 0)
u = A.fail[u];
u = A.g[u][v];
dp[nxt][u] = dp[nxt][u] + dp[now][i];
}
}
}
int now = (M&1);
bign ans = 0;
for (int i = 0; i < n; i++) {
if (A.tag[i] || A.last[i])
continue;
ans = ans + dp[now][i];
}
ans.Put();
printf("\n");
}
int main () {
while (scanf("%d%d%d%*c", &N, &M, &K) == 3) {
A.init();
gets(s);
for (int i = 0; i < N; i++)
tab[i] = s[i] + bw;
for (int i = 1; i <= K; i++) {
gets(s);
A.insert(s, i);
}
A.getFail();
solve();
}
return 0;
}
void Aho_Corasick::init() {
sz = 1;
tag[0] = 0;
memset(g[0], 0, sizeof(g[0]));
}
int Aho_Corasick::idx(char ch) {
return ch + bw;
}
void Aho_Corasick::put(int x, int y) {
}
void Aho_Corasick::insert(char* str, int k) {
int u = 0, n = strlen(str);
for (int i = 0; i < n; i++) {
int v = idx(str[i]);
if (g[u][v] == 0) {
tag[sz] = 0;
memset(g[sz], 0, sizeof(g[sz]));
g[u][v] = sz++;
}
u = g[u][v];
}
tag[u] = k;
}
void Aho_Corasick::match(char* str) {
int n = strlen(str), u = 0;
for (int i = 0; i < n; i++) {
int v = idx(str[i]);
while (u && g[u][v] == 0)
u = fail[u];
u = g[u][v];
if (tag[u])
put(i, u);
else if (last[u])
put(i, last[u]);
}
}
void Aho_Corasick::getFail() {
queue<int> que;
for (int i = 0; i < sigma_size; i++) {
int u = g[0][i];
if (u) {
fail[u] = last[u] = 0;
que.push(u);
}
}
while (!que.empty()) {
int r = que.front();
que.pop();
for (int i = 0; i < sigma_size; i++) {
int u = g[r][i];
if (u == 0) {
g[r][i] = g[fail[r]][i];
continue;
}
que.push(u);
int v = fail[r];
while (v && g[v][i] == 0)
v = fail[v];
fail[u] = g[v][i];
last[u] = tag[fail[u]] ? fail[u] : last[fail[u]];
}
}
}
void bign::delzero () {
while (len && num[len-1] == 0)
len--;
if (len == 0) {
num[len++] = 0;
}
}
void bign::Put () {
for (int i = len-1; i >= 0; i--)
printf("%d", num[i]);
}
void bign::operator = (char* number) {
len = strlen (number);
for (int i = 0; i < len; i++)
num[i] = number[len-i-1] - ‘0‘;
delzero ();
}
void bign::operator = (int number) {
len = 0;
while (number) {
num[len++] = number%10;
number /= 10;
}
delzero ();
}
bign bign::operator + (const int& b) {
bign a = b;
return *this + a;
}
bign bign::operator + (const bign& b) {
int bignSum = 0;
bign ans;
for (int i = 0; i < len || i < b.len; i++) {
if (i < len) bignSum += num[i];
if (i < b.len) bignSum += b.num[i];
ans.num[ans.len++] = bignSum % 10;
bignSum /= 10;
}
while (bignSum) {
ans.num[ans.len++] = bignSum % 10;
bignSum /= 10;
}
return ans;
}
时间: 2024-10-25 13:08:12