hdu1841 kmp（用最短的串使包含存在的两个串）
1.大的包含小的，求kmp即可
2.一个串的前缀是另一个串的后缀，合并利用next数组
1 #include<stdio.h> 2 #include<string.h> 3 char s1[1000005],s2[1000005],t1[1000005],t2[1000005]; 4 char s[2000005]; 5 int next[2000005]; 6 int find(char *A,char *B,int n,int m) 7 { 8 int i,j=0; 9 for (i=1;i<=n;i++) 10 { 11 while (j>0&&B[j+1]!=A[i]) j=next[j]; 12 if (B[j+1]==A[i]) j++; 13 if (j==m) return i-m+1; 14 } 15 return -1; 16 } 17 void getnext(char *B,int m) 18 { 19 int i,j; 20 next[1]=j=0; 21 for (i=2;i<=m;i++) 22 { 23 while (j>0&&B[j+1]!=B[i]) j=next[j]; 24 if (B[j+1]==B[i]) j++; 25 next[i]=j; 26 } 27 } 28 int main() 29 { 30 int T,len1,len2,n,tmp,i,minx; 31 scanf("%d",&T); 32 while (T--) 33 { 34 scanf("%s%s",s1,s2); 35 len1=strlen(s1); len2=strlen(s2); 36 n=len1+len2; 37 if (len1<len2){ 38 tmp=len1; len1=len2; len2=tmp; 39 strcpy(s,s1); strcpy(s1,s2); strcpy(s2,s); 40 } 41 for (i=len1;i>=1;i--) t1[i]=s1[i-1]; 42 for (i=len2;i>=1;i--) t2[i]=s2[i-1]; 43 getnext(t2,len2); 44 if (find(t1,t2,len1,len2)>0) {printf("%d\n",len1);continue;} 45 strcpy(s,s1); strcat(s,s2); 46 for (i=n;i>=1;i--) s[i]=s[i-1]; 47 getnext(s,n); tmp=n; 48 while (next[tmp]>0&&next[tmp]>len2) tmp=next[tmp]; 49 minx=n-next[tmp]; 50 strcpy(s,s2); strcat(s,s1); 51 for (i=n;i>=1;i--) s[i]=s[i-1]; 52 getnext(s,n); tmp=n; 53 while (next[tmp]>0&&next[tmp]>len2) tmp=next[tmp]; 54 if (n-next[tmp]<minx) minx=n-next[tmp]; 55 printf("%d\n",minx); 56 } 57 }
