#include <stdio.h> int find_pattern(int *mem, int n) { for (int *p = mem, count = 0; p < mem + n - 1; ++p) { count = (*(p + 1) - *p == 1) ? count + 1 : 0; if (count == 2) return (p + 1 - count) - mem; } 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