HDU - 2087 剪花布条(kmp)
题意:求w串在T串中的出现次数。(不可重叠出现)
#include<cstdio> #include<cstring> #include<cstdlib> #include<cctype> #include<cmath> #include<iostream> #include<sstream> #include<iterator> #include<algorithm> #include<string> #include<vector> #include<set> #include<map> #include<stack> #include<deque> #include<queue> #include<list> #define lowbit(x) (x & (-x)) const double eps = 1e-8; inline int dcmp(double a, double b){ if(fabs(a - b) < eps) return 0; return a > b ? 1 : -1; } typedef long long LL; typedef unsigned long long ULL; const int INT_INF = 0x3f3f3f3f; const int INT_M_INF = 0x7f7f7f7f; const LL LL_INF = 0x3f3f3f3f3f3f3f3f; const LL LL_M_INF = 0x7f7f7f7f7f7f7f7f; const int dr[] = {0, 0, -1, 1, -1, -1, 1, 1}; const int dc[] = {-1, 1, 0, 0, -1, 1, -1, 1}; const int MOD = 1e9 + 7; const double pi = acos(-1.0); const int MAXN = 1000 + 10; const int MAXT = 1000000 + 10; using namespace std; char s1[MAXN], s2[MAXN]; int len1, len2; int Next[MAXN]; void getNext(){ Next[0] = 0; for(int p = 1, k = 0; p < len2; ++p){ while(k > 0 && s2[p] != s2[k]) k = Next[k - 1]; if(s2[p] == s2[k]) ++k; Next[p] = k; } } int kmp(){ getNext(); int cnt = 0; for(int p = 0, k = 0; p < len1; ++p){ while(k > 0 && s1[p] != s2[k]) k = Next[k - 1]; if(s1[p] == s2[k]) ++k; if(k == len2){ ++cnt; k = 0; } } return cnt; } int main(){ while(scanf("%s", s1) == 1){ if(strcmp(s1, "#") == 0) return 0; scanf("%s", s2); len1 = strlen(s1); len2 = strlen(s2); printf("%d\n", kmp()); } return 0; }