repeated_sequences.c

/*

    repeated_sequences.c

    Task:

A 8-years old boy was learning to play Piano.
He played several musical notes that are combination of ‘C’, ‘D’, ‘E’, ‘F’, ‘G’.
For example, he played "CCGCCGGCCG" on the Piano.
He wants to identify repeated sequences within his played musical notes.
Given a string s that represents a sequence of musical notes,
write a program to return all the 10-letter-long sequences (substrings)
that occur more than once in the s. You may return the answer in any order.

Example 1:
Input: s = "CCCCCDDDDDCCCCCDDDDDCCCCCFFGG"
Output: CCCCCDDDDD CCCCDDDDDC CCCDDDDDCC CCDDDDDCCC CDDDDDCCCC DDDDDCCCCC

Example 2:
Input: s = "CCCCCCCCCCCCC"
Output: CCCCCCCCCC


    You can find all my C programs at Dragan Milicev's pastebin:

    https://pastebin.com/u/dmilicev

*/

#include <stdio.h>
#include <string.h>

#define SUB_LEN 10

int main(void){
    char s[] = "CCCCCDDDDDCCCCCDDDDDCCCCCFFGG";
    //char s[] = "CCCCCCCCCCCCC";
    char subs[100][SUB_LEN];
    int i, j, k, s_len=strlen(s), total_sub_count=0, sub_count=0;

    printf("\n SUB_LEN = %d  ,  s_len = %d  ,  s = |%s| \n\n",SUB_LEN,s_len,s);
    printf("\n   s[j]     subs[i]     result \n\n");


    for(i=0;i<s_len-SUB_LEN+1;i++){
        k=0;
        for(j=i;j<i+SUB_LEN;j++){
            printf("%c",s[j]);
            subs[i][k++]=s[j];
        }
        subs[i][k]='\0';    // finish the substring
        total_sub_count++;
        printf("|%s|",subs[i]);
        if( strstr(&s[i+1],subs[i]) ){
            printf("%s",subs[i]);
            sub_count++;
        }
        printf("\n");
    }
    printf("\n There are total %d substrings of length %d. \n", total_sub_count, SUB_LEN);
    printf("\n There are %d substrings of length %d that occur more than once in the s. \n\n",
            sub_count, SUB_LEN);


    return 0;
} // main()