bzoj4462: [Jsoi2013]编程作业

KMP还是有点用处的嘛qwq

对于小写字母，修改其为前一个这个小写字母和它的距离

然后跑KMP就行了

跑得飞快

#include <iostream>
#include <cstdio>
#include <cmath>
#include <cstring>
#include <cstdlib>
#include <algorithm>
#define N 1000006
#define M 100005

using namespace std;
int nxt[M],m,pre_mode[M];char mode[M];
int n,pre[N];char s[N];
int last[256];
bool equal(int x,int y,int nowlen){
	return x==y||x>nowlen&&y>nowlen;
}

void work(){
	scanf("%s%s",s+1,mode+1);
	n=strlen(s+1);m=strlen(mode+1);

	memset(last,0,sizeof(last));
	for (int i=1;i<=m;++i)
		if (mode[i]>'Z'){pre_mode[i]=i-last[mode[i]];last[mode[i]]=i;}
		else pre_mode[i]=-mode[i];
	memset(last,0,sizeof(last));
	for (int i=1;i<=n;++i)
		if (s[i]>'Z'){pre[i]=i-last[s[i]];last[s[i]]=i;}
		else pre[i]=-s[i];

	int j=nxt[0]=nxt[1]=0;
	for (int i=2;i<=m;++i){
		while (j&&!equal(pre_mode[j+1],pre_mode[i],j)) j=nxt[j];
		if (equal(pre_mode[j+1],pre_mode[i],j)) ++j;
		nxt[i]=j;
	}
	j=0;
	int ans=0;
	for (int i=1;i<=n;++i){
		while (j&&!equal(pre_mode[j+1],pre[i],j)) j=nxt[j];
		if (equal(pre_mode[j+1],pre[i],j)) ++j;
		if (j==m){++ans;j=nxt[j];}
	}
	printf("%d\n",ans);
}

int main(){
	int T;scanf("%d",&T);
	while (T--) work();
	return 0;
}