POJ Oulipo(KMP模板题)

时间:2024-10-08 18:06:14

题意:找出模板在文本串中出现的次数

思路:KMP模板题

#include<cstdio>
#include<cstring>
#include<cmath>
#include<cstdlib>
#include<iostream>
#include<algorithm>
#include<vector>
#include<map>
#include<queue>
#include<stack>
#include<string>
#include<map>
#include<set>
#include<ctime>
#define eps 1e-6
#define LL long long
#define pii (pair<int, int>)
//#pragma comment(linker, "/STACK:1024000000,1024000000")
using namespace std; const int maxt = 1000000 + 100;
const int maxp = 10000 + 100;
//const int INF = 0x3f3f3f3f; char P[maxp], T[maxt];
int f[maxp]; void getFail() {
int m = strlen(P);
f[0] = 0; f[1] = 0;
for(int i = 1; i < m; i++) {
int j = f[i];
while(j && P[i]!=P[j]) j = f[j];
f[i+1] = P[i]==P[j] ? j+1 : 0;
}
} int find_p() {
int ans = 0;
int n = strlen(T), m = strlen(P);
getFail();
int j = 0;
for(int i = 0; i < n; i++) {
while(j && P[j]!=T[i]) j = f[j];
if(P[j] == T[i]) j++;
if(j == m) ans++, j=f[j];
}
return ans;
} int main() {
//freopen("input.txt", "r", stdin);
int t; cin >> t;
while(t--) {
scanf("%s%s", P, T);
int ans = find_p();
cout << ans << endl;
}
return 0;
}