HDU 4749-Parade Show（KMP变形）

#include <map>
#include <set>
#include <list>
#include <cmath>
#include <queue>
#include <stack>
#include <cstdio>
#include <vector>
#include <string>
#include <cctype>
#include <complex>
#include <cassert>
#include <utility>
#include <cstring>
#include <cstdlib>
#include <iostream>
#include <algorithm>
using namespace std;
typedef pair<int,int> PII;
typedef long long ll;
#define lson l,m,rt<<1
#define pi acos(-1.0)
#define rson m+1,r,rt<<11
#define All 1,N,1
#define read freopen("in.txt", "r", stdin)
const ll  INFll = 0x3f3f3f3f3f3f3f3fLL;
const int INF= 0x7ffffff;
const int mod =  1000000007;
int x[100010],a[100010];
int f[100010];
bool cmp(int i,int c[],int j,int d[]){
if(c[i]*d[j]>0)return true;
if(c[i]==0&&d[j]==0)return true;
return false;
}
void hand(int n,int m){
for(int i=0;i<n;++i)
x[i]=x[i+1]-x[i];
for(int i=0;i<m;++i)
a[i]=a[i+1]-a[i];
}
void getnext(int m){
int i=0,j=-1;
f[0]=-1;
while(i<m){
if(j==-1||cmp(i,a,j,a)){
i++;
j++;
f[i]=j;
}
else j=f[j];
}
}
void solve(int n,int m){
getnext(m);
int i=0,j=0,num=0;
while(i<n){
if(cmp(i,x,j,a)||j==-1){
i++;
j++;
}
else j=f[j];
if(j==m){
i++;
j=0;
num++;
}
}
printf("%d\n",num);
}
int main()
{
int n,m,k;
while(scanf("%d%d%d",&n,&m,&k)!=EOF){
for(int i=0;i<n;++i){
scanf("%d",&x[i]);
}
for(int i=0;i<m;++i){
scanf("%d",&a[i]);
}
if(m==1){
printf("%d\n",n);
continue;
}
hand(n-1,m-1);
solve(n-1,m-1);
}
return 0;
}