#include <stdio.h>
int find_pattern(int *mem, int n) {
// Write your pointer-based logic here
int index = 0;
int prev = *mem;
mem++;
int count =1;
int id = 0;
for(int i=0; i<n; ++i)
{
// printf("%d",index);
if(count == 3)
{
break;
}
else if(*mem != (prev+1))
{
if(id)
{
index += 2;
}
else
{
index++;
}
id = 0;
count =1;
}
else
{
id++;
count++;
}
prev = *mem;
mem++;
}
if(count == 3)
{
return index;
}
return -1;
}
int main() {
int n, arr[100];
scanf("%d", &n);
for (int i = 0; i < n; i++) {
scanf("%d", &arr[i]);
}
int res = find_pattern(arr, n);
printf("%d", res);
return 0;
}
Input
8 2 4 5 6 9 11 12 14
Expected Output
1