HDU 2594 Simpsons 'den den Talents KMP

Question: Give you two strings s1 and s2. Ask you to find a substring t with the maximum length. t is the prefix of s1 and is the suffix of s2. The length of t and t is output, if it does not exist, 0 is output directly.

 

 

1. directly request next

# Include <iostream> # include <cstdio> # include <cstdlib> # include <cmath> # include <cstring> # include <string> # include <vector> # include <list> # include <deque> # include <queue> # include <iterator> # include <stack> # include <map> # include <set> # include <algorithm> # include <cctype> using namespace std; typedef long LL; const int N = 50005; const ll ii = 100000000; const int INF = 0x3f3f3f; const Double PI = acos (-1.0); int next [2 * N], len; char str [2 * N], xh [N]; void getnext (char * p) {int j = 0, k =-1; next [0] =-1; while (j <len) // len is the length of p {if (k =-1 | p [j] = p [k]) {j ++; k ++; next [j] = k;} else k = next [k];} int main () {int I, j, T; while (scanf ("% s", str, xh )! = EOF) {int len1 = strlen (str), len2 = strlen (xh); len = len1 + len2; strcat (str, xh); getnext (str ); while (next [len]> len1 | next [len]> len2) {len = next [len];} str [next [len] = '\ 0 '; if (next [len] = 0) printf ("0 \ n"); else printf ("% s % d \ n", str, next [len]);} return 0 ;} # include <iostream> # include <cstdio> # include <cstdlib> # include <cmath> # include <cstring> # include <string> # include <vector> # include <list> # include <d Eque> # include <queue> # include <iterator> # include <stack> # include <map> # include <set> # include <algorithm> # include <cctype> using namespace std; typedef long LL; const int N = 50005; const ll ii = 100000000; const int INF = 0x3f3f3f; const double PI = acos (-1.0 ); int next [2 * N], len; char str [2 * N], xh [N]; void getnext (char * p) {int j = 0, k =-1; next [0] =-1; while (j <len) // len is the length of p {if (k =-1 | p [j] = p [k]) {j ++; k ++; Next [j] = k;} else k = next [k];} int main () {int I, j, T; while (scanf ("% s", str, xh )! = EOF) {int len1 = strlen (str), len2 = strlen (xh); len = len1 + len2; strcat (str, xh); getnext (str ); while (next [len]> len1 | next [len]> len2) {len = next [len];} str [next [len] = '\ 0 '; if (next [len] = 0) printf ("0 \ n"); else printf ("% s % d \ n", str, next [len]);} return 0 ;}

2. KMP match: Use s1 as the mode string and s2 as the main string, and directly use kmp

#include <cstdio>  #include <cstring>  using namespace std;  const int N = 50002; char str1[N]; char str2[N]; int next[N];  void get_next(int len_1); int kmp_search(int len_1, int len_2);  int main() {     int len;     while(scanf("%s%s", str1, str2) != EOF)     {         int len_1 = strlen(str1);         int len_2 = strlen(str2);         get_next(len_1);         len = kmp_search(len_1, len_2);         if(len == 0)         {             printf("0\n");         }         else         {             for(int i = 0; i < len; i++)             {                 printf("%c", str1[i]);             }             printf(" %d\n", len);         }     }     return 0; }  void get_next(int len_1) {     int i = 0;     int j = -1;     next[i] = -1;     while(i < len_1)     {         if(j == -1 || str1[j] == str1[i])         {             i++;             j++;             if(str1[i] == str1[j])             {                 next[i] = next[j];             }             else             {                 next[i] = j;             }         }         else         {             j = next[j];         }     } }  int kmp_search(int len_1, int len_2) {     int i = 0;     int j = 0;     while(i < len_2)     {         if(j == -1 || str1[j] == str2[i])         {             i++;             j++;         }         else         {             j = next[j];         }     }     if(j == -1)     {         return 0;     }     if(j == 0)     {         if(str1[0] == str2[len_2 - 1])         {             return 1;         }         else         {             return 0;         }     }     else     {         return j;     } } #include <cstdio>#include <cstring>using namespace std;const int N = 50002;char str1[N];char str2[N];int next[N];void get_next(int len_1);int kmp_search(int len_1, int len_2);int main(){    int len;    while(scanf("%s%s", str1, str2) != EOF)    {        int len_1 = strlen(str1);        int len_2 = strlen(str2);        get_next(len_1);        len = kmp_search(len_1, len_2);        if(len == 0)        {            printf("0\n");        }        else        {            for(int i = 0; i < len; i++)            {                printf("%c", str1[i]);            }            printf(" %d\n", len);        }    }    return 0;}void get_next(int len_1){    int i = 0;    int j = -1;    next[i] = -1;    while(i < len_1)    {        if(j == -1 || str1[j] == str1[i])        {            i++;            j++;            if(str1[i] == str1[j])            {                next[i] = next[j];            }            else            {                next[i] = j;            }        }        else        {            j = next[j];        }    }}int kmp_search(int len_1, int len_2){    int i = 0;    int j = 0;    while(i < len_2)    {        if(j == -1 || str1[j] == str2[i])        {            i++;            j++;        }        else        {            j = next[j];        }    }    if(j == -1)    {        return 0;    }    if(j == 0)    {        if(str1[0] == str2[len_2 - 1])        {            return 1;        }        else        {            return 0;        }    }    else    {        return j;    }}