#include <stdio.h> int find_pattern(int *mem, int n) { for(int i = 0; i < n - 2; i++) { int pattern_idx = i; int pattern_count = 1; for(int j = i; j < n; j++) { if ((*(mem + j) + 1) == *(mem + j + 1)) { pattern_count++; } else { break; } if (pattern_count == 3) { return pattern_idx; } } } 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