51nod 1532 带可选字符的多字符串匹配(dp、bitset优化)
题意:
$N\le 2\times 10^6的母串,M\le 500的模式串$
$模式串的每个字符c_i有cnt_i\le 62个可选字符$
$求母串哪些位置可以匹配模式串$
分析:
$f[i][j]:=母串匹配到i,模式串匹配到j,能否匹配$
$把所有可选字符压起来成LL,复杂度是O(nm)的,并不行$
$f[i][j]=f[i-1][j-1],t[j]>>s[i] and 1为真$
$由于dp状态是bool,并且状态只与i-1有关,考虑bitset压位$
$预处理出模式串字符集在模式串的位置到bitset中$
$每次转移只要左移一次然后与母串字符的状态即可$
$这样就能一次直接转移整个模式串的状态$
$时间复杂度为O(nm/64)$
$表示百毒之星的那个数据其实是有毒的,贴个两边都能过的$
$(参考了百毒之星ranklist的那个人的如何在坑爹数据下的过题办法。。$
代码:
//
// Created by TaoSama on 2016-07-23
// Copyright (c) 2016 TaoSama. All rights reserved.
//
#pragma comment(linker, "/STACK:102400000,102400000")
#include <algorithm>
#include <cctype>
#include <cmath>
#include <cstdio>
#include <cstdlib>
#include <cstring>
#include <ctime>
#include <iomanip>
#include <iostream>
#include <map>
#include <queue>
#include <string>
#include <set>
#include <vector>
#include <bitset>
using namespace std;
#define pr(x) cout << #x << " = " << x << " "
#define prln(x) cout << #x << " = " << x << endl
const int N = 2e6 + 10, INF = 0x3f3f3f3f, MOD = 1e9 + 7;
const int M = 500 + 10;
int n;
char s[N], t[M];
typedef bitset<M> Sta;
Sta f[2], g[256]; //f[M][N]
int main() {
#ifdef LOCAL
freopen("C:\\Users\\TaoSama\\Desktop\\in.txt", "r", stdin);
// freopen("C:\\Users\\TaoSama\\Desktop\\out.txt","w",stdout);
#endif
ios_base::sync_with_stdio(0);
clock_t _ = clock();
while(gets(s + 1)) {
scanf(" %d", &n);
for(int i = 0; i < 256; ++i) g[i].reset();
for(int i = 1; i <= n; ++i) {
int cnt; scanf("%d%s", &cnt, t + 1);
for(int j = 1; j <= cnt; ++j) g[t[j]][i] = 1;
}
bool ok = false;
int p = 0;
f[p].reset();
f[p][0] = 1;
for(int i = 1; s[i]; ++i) {
f[!p] = (f[p] << 1) & g[s[i]];
f[!p][0] = 1;
if(f[!p][n]) {
ok = true;
printf("%d\n", i - n + 1);
}
p = !p;
}
if(!ok) puts("NULL");
scanf("%*c");
}
#ifdef LOCAL
printf("\nTime cost: %.2fs\n", 1.0 * (clock() - _) / CLOCKS_PER_SEC);
#endif
return 0;
}