hihoCoder 1015 KMP算法

#include <cstdio>
#include <cmath>
#include <cctype>
#include <bitset>
#include <algorithm>
#include <cstring>
#include <utility>
#include <string>
#include <iostream>
#include <map>
#include <set>
#include <vector>
#include <queue>
#include <stack>
using namespace std;
#pragma comment(linker, "/STACK:1024000000,1024000000")
#define eps 1e-10
#define inf 0x3f3f3f3f
#define PI pair<int, int>
typedef long long LL;
const int maxn = 1e4 + 5;
char T[maxn*100], p[maxn];
int nex[maxn];
void getNext(char *P, int *nex, int len) {
nex[0]= -1;
for(int i = 1; i < len; ++i)    {
int j = nex[i-1];
while(j >= 0 && p[j+1] != p[i]) j = nex[j];
if(p[j+1] == p[i]) nex[i] = j+1;
else nex[i] = -1;
}
}
//统计模式串出现的次数
int KMP(char *T, char *p, int *nex) {
int n = strlen(T), m = strlen(p);
getNext(p, nex, m);
int j = -1, cnt = 0;
for(int i = 0; i < n; ++i) {
while(j >= 0 && T[i] != p[j+1]) j = nex[j];
if(T[i] == p[j+1]) j++;
if(j == m-1) {
cnt++;
j = nex[j];
}
}
return cnt;
}
int main() {
int n;
scanf("%d", &n);
while(n--) {
scanf("%s%s", p, T);
printf("%d\n", KMP(T, p, nex));
}
return 0;
}