KMP算法。

// bjtu1394.cpp#include <cstdio>#include <cstring>#include <cmath>#include <cstdlib>#include <iostream>#include <algorithm>#include <vector>#include <map>#include <set>#define out(v) cout << #v << ": " << (v) << endl#define SZ(v) ((int)(v).size())using namespace std;typedef long long LL;int CS;char W[10000 + 5];char T[1000000 + 5];int LW, LT;int next[10000 + 5];void getnext(){next[0] = -1;// 算到LW是有必要的，多次匹配时会用到 for (int i = 1, j = -1; i <= LW; ++i) {while (j != -1 && W[j] != W[i - 1]) j = next[j];next[i] = ++j;}}int main(){scanf("%d", &CS);getchar();while (CS--){gets(W); LW = strlen(W);gets(T); LT = strlen(T);getnext();int i = 0, j = 0, cnt = 0;while (i < LT){while (j != -1 && T[i] != W[j]) j = next[j];++i, ++j;if (j == LW) {++cnt;j = next[j];}}printf("%d/n", cnt);}return 0;}