is a given array a sub sequence of another array - c

Question

building a code that will check if a group of numbers in s_array[] is a sub-sequence of array[], that means that { 1, 5, 4 } is not a sub-sequence of array, whereas { 1, 4, 5} is one (order matters)
my code will first check if the first element of s_array[] exists in array[], once a common element is found it will proceed to check if the rest of s_array[]'s elements also exist in array[] and in the same order (other elements can be between them)
#include <stdio.h>
void main(){
int s_array[] = { 5, 7, 13 };
int array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
int i, Bcount, m, counter = 1, j = 4;
//i, Bcount and m are loop counters
//counter will count number of repeated elements
//j is the number of elements in s_array + 1
for( i = 0; i <= 15; i++ ){
if( s_array[0] == array[i] ){ // does the first element exist?
for( Bcount = 1; Bcount < j; Bcount++ ){ //checking the rest
for( m = i; m < 15; m++){
if( s_array[Bcount] == array[m] ){
counter++;
i = m;
break;
}
}
}
}
if( j == counter ){
printf( "B is a sub-sequence of A.\n" );
break;
}
else{
printf( "B is not a sub-sequence of A.\n" );
break;
}
}
}
and honestly I can't see if it is the algorithm or that I did something wrong with the coding

Answer 1

First of all the first loop is wrong as i goes up to 15 and at this index you access array out of bounds (undefined behavior).
Then the loop is quite simple. You only need
one loop i index for array and si for s_array
only increment si if you find the number array[i] at s_array[si]
stop the loop if i covered array, or if si got the number of sub array elements (3)
if si is at least 3, the sub sequence was found
That is
int s_array[] = { 5, 7, 13 };
int array[] = { 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15 };
int si,i;
for (si=0,i=0 ; i<15 && si<3 ; i++) {
if (s_array[si] == array[i]) si++;
}
printf ("Sub was %s\n", si<3 ? "not found":"found");

Answer 2

Should J not be equal to 3 and the first fot loop index to 14 (or make it strictly less than 15 rather than less than or equal to)? In your second for loop j may be equal to 3 and s_array[3] is invalid. I would try something like:
Bcount = 0;
counter = 1;
for( i = 0; i <= 14; i++ ){
if( s_array[Bcount] == array[i] ){
counter++;
Bcount++;
if(counter == 3){
printf("Success");
break;
}
}
}

Answer 3

In your example, the problem is that the loop get's terminated by the outer if condition:
if( j == counter ){
printf( "B is a sub-sequence of A.\n" );
break;
}
else{
printf( "B is not a sub-sequence of A.\n" );
break;
}
after the first loop cycle, the program checks this condition and breaks.
This condition should be outside the loop.