#include <stdio.h> int find_pattern(int *mem, int n) { if (n < 3) { return -1; } int *start = mem; int index = 0; while (index <= n - 3) { if (*(start + 1) == *(start) + 1 && *(start + 2) == *(start + 1) + 1) { return index; } start++; 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; }
Test Cases
Test Results
Input
8 2 4 5 6 9 11 12 14
Expected Output
1