[TJOI2017]DNA

嘟嘟嘟




这题怎么想都想不出来，最后还是敲了暴力，喜提40分……




正解竟然也是暴力……

用\(s_0\)构造SAM，然后把\(s\)扔上去暴力dfs：记录一个修改次数tot，如果当前不匹配，就tot + 1并且往下跳……

反正就是过了……

记得多组数据，清空数组。

#include<cstdio>
#include<iostream>
#include<cmath>
#include<algorithm>
#include<cstring>
#include<cstdlib>
#include<cctype>
#include<vector>
#include<stack>
#include<queue>
using namespace std;
#define enter puts("")
#define space putchar(' ')
#define Mem(a, x) memset(a, x, sizeof(a))
#define In inline
typedef long long ll;
typedef double db;
const int INF = 0x3f3f3f3f;
const db eps = 1e-8;
const int maxn = 1e5 + 5;
inline ll read()
{
  ll ans = 0;
  char ch = getchar(), last = ' ';
  while(!isdigit(ch)) last = ch, ch = getchar();
  while(isdigit(ch)) ans = (ans << 1) + (ans << 3) + ch - '0', ch = getchar();
  if(last == '-') ans = -ans;
  return ans;
}
inline void write(ll x)
{
  if(x < 0) x = -x, putchar('-');
  if(x >= 10) write(x / 10);
  putchar(x % 10 + '0');
}

int n, m, ans = 0, val[200];
char s[maxn];

struct Sam
{
  int las, cnt;
  int tra[maxn << 1][5], len[maxn << 1], link[maxn << 1], siz[maxn << 1];
  In void insert(int c)
  {
    int now = ++cnt, p = las;
    len[now] = len[las] + 1; siz[now] = 1;
    while(~p && !tra[p][c]) tra[p][c] = now, p = link[p];
    if(p == -1) link[now] = 0;
    else
      {
	int q = tra[p][c];
	if(len[q] == len[p] + 1) link[now] = q;
	else
	  {
	    int clo = ++cnt;
	    len[clo] = len[p] + 1;
	    memcpy(tra[clo], tra[q], sizeof(tra[q]));
	    link[clo] = link[q], link[q] = link[now] = clo;
	    while(~p && tra[p][c] == q) tra[p][c] = clo, p = link[p];
	  }
      }
    las = now;
  }
  int buc[maxn << 1], pos[maxn << 1];
  In void sort()
  {
    for(int i = 1; i <= cnt; ++i) ++buc[len[i]];
    for(int i = 1; i <= cnt; ++i) buc[i] += buc[i - 1];
    for(int i = 1; i <= cnt; ++i) pos[buc[len[i]]--] = i;
    for(int i = cnt; i; --i) siz[link[pos[i]]] += siz[pos[i]];
  }
  In void dfs(int p, int len, int tot)
  {
    if(tot > 3) return;
    if(len >= m) {ans += siz[p]; return;}
    for(int c = 1; c <= 4; ++c)
      {
	if(!tra[p][c]) continue;
	if(c == val[s[len]]) dfs(tra[p][c], len + 1, tot);
	else dfs(tra[p][c], len + 1, tot + 1);
      }
  }
  In void init()
  {
    Mem(tra, 0), Mem(link, 0), Mem(len, 0), Mem(siz, 0);
    link[las = cnt = 0] = -1;
    Mem(buc, 0), Mem(pos, 0);
  }
}S;

int main()
{
  val['A'] = 1, val['T'] = 2, val['G'] = 3, val['C'] = 4;
  int T = read();
  while(T--)
    {
      S.init(); ans = 0;
      scanf("%s", s); n = strlen(s);
      for(int i = 0; i < n; ++i) S.insert(val[s[i]]);
      S.sort();
      scanf("%s", s); m = strlen(s);
      S.dfs(0, 0, 0);
      write(ans), enter;
    }
  return 0;
}