KMP算法的应用。
1 #include <stdio.h> 2 #include <string.h> 3 4 #define MAXNUM 100005 5 6 char src[MAXNUM], des[MAXNUM]; 7 char src1[MAXNUM*2], des1[MAXNUM*2]; 8 int next[MAXNUM]; 9 10 void getnext(char *p, int *next, int len) { 11 int j, k; 12 j = 0; 13 k = -1; 14 next[0] = -1; 15 while (j+1 < len) { 16 if (k==-1 || p[j]==p[k]) { 17 ++j; 18 ++k; 19 if (p[j] == p[k]) 20 next[j] = next[k]; 21 else 22 next[j] = k; 23 } else { 24 k = next[k]; 25 } 26 } 27 } 28 29 int kmp(char *src, char *des, int lens, int lend) { 30 int i, j; 31 32 i = j = 0; 33 memset(next, 0, sizeof(next)); 34 getnext(des, next, lend); 35 while (i < lens) { 36 while (src[i] != des[j]) { 37 if (next[j] == -1) { 38 j = 0; 39 break; 40 } 41 j = next[j]; 42 } 43 if (src[i] == des[j]) 44 ++j; 45 ++i; 46 } 47 48 return j; 49 } 50 51 int main() { 52 int i, j, k; 53 char *p, *q; 54 int lens, lend; 55 56 while (scanf("%s %s", src, des) != EOF) { 57 lens = strlen(src); 58 lend = strlen(des); 59 j = kmp(src, des, lens, lend); 60 k = kmp(des, src, lend, lens); 61 if (j == k) { 62 strcpy(src1, src); 63 for (i=j; i<lend; ++i) 64 src1[lens++] = des[i]; 65 src1[lens] = ' '; 66 strcpy(des1, des); 67 for (i=k; i<lens; ++i) 68 des1[lend++] = src[i]; 69 des1[lend] = ' '; 70 if (strcmp(src1, des1) < 0) { 71 printf("%s ", src1); 72 } else { 73 printf("%s ", des1); 74 } 75 continue; 76 } else if (j > k) { 77 p = src; 78 q = des; 79 } else { 80 p = des; 81 q = src; 82 j = k; 83 } 84 printf("%s", p); 85 printf("%s ", q+j); 86 } 87 88 return 0; 89 }