| int longestPalindrom(char *s, int n, char *output) | |
| { | |
| int i = 0; | |
| int j = 0; | |
| int len = 0; | |
| int id = 0; | |
| int limit = 0; | |
| int maxLen = 0; | |
| int maxId = 0; | |
| int r = 0; | |
| int mirror = 0; | |
| int ret = 0; | |
| char s2[2003]; | |
| int p[2003]; | |
| p[0] = 0; | |
| s2[0] = 36; | |
| while (i < n) { | |
| s2[2 * i + 1] = 35; | |
| s2[2 * i + 2] = s[i]; | |
| i++; | |
| } | |
| s2[2 * i + 1] = 35; | |
| len = 2 * i + 2; | |
| s2[len] = 0; | |
| id = 0; | |
| limit = 0; | |
| maxLen = 0; | |
| maxId = 0; | |
| i = 1; | |
| while (i < len) { | |
| if (i < limit) { | |
| mirror = 2 * id - i; | |
| if (p[mirror] < limit - i) { | |
| r = p[mirror]; | |
| p[i] = r; | |
| } else { | |
| r = limit - i; | |
| p[i] = r; | |
| } | |
| } else { | |
| r = 1; | |
| p[i] = r; | |
| } | |
| while (s2[i + r] == s2[i - r]) { | |
| r++; | |
| p[i] = r; | |
| } | |
| if (i + r > limit) { | |
| limit = i + r; | |
| id = i; | |
| } | |
| r = r - 1; | |
| if (maxLen < r) { | |
| maxLen = r; | |
| maxId = i; | |
| } | |
| r = 0; | |
| mirror = 0; | |
| i++; | |
| } | |
| j = 0; | |
| i = maxId - maxLen; | |
| while (i <= maxId + maxLen) { | |
| if (s2[i] != 35) { | |
| output[j] = s2[i]; | |
| j++; | |
| } | |
| i++; | |
| } | |
| output[j] = 0; | |
| ret = maxLen; | |
| return ret; | |
| } | |