編程珠璣 15.2 短語

尋找字串中最長重複字串，方法:

尾碼數組 + 快排

代碼如下：

/* * pp_15_2.cpp * *  Created on: 2012-5-31 *      Author: ict */#include <cstdio>#include <cstdlib>#include <algorithm>#include <cstring>using namespace std;#define MAXN 10000//qsort比較函數//這個函數注意指標的轉換，需要理解？？？int pstrcmp(const void *a, const void *b){return strcmp((char *)*(int *)a, (char *)*(int *)b);//注意一定是(char *)*(int *)a，而不是(char *)*(char *)a}//比較兩個字串之間相同長度int comlen(char *a, char *b){int i = 0;while(*a && *b && (*a++ == *b++))i++;return i;}int main(){char c[MAXN];char *a[MAXN];char ch;int n;n = 0;//setbuf(stdout, NULL);FILE *fp;fp = fopen("c:\\data.txt", "r");while(fscanf(fp, "%c", &ch) != EOF){a[n] = &c[n];c[n++] = ch;}c[n] = '\0';//排序尾碼數組qsort(a, n, sizeof(char *), pstrcmp);int maxlen = 0;int maxi;for(int i= 0; i < n - 1; i++){if(comlen(a[i], a[i+1]) > maxlen){maxlen = comlen(a[i], a[i+1]);maxi = i;}}printf("%.*s\n", maxlen, a[maxi]);return 0;}