#include <stdio.h> int find_pattern(int *memory, int n) { int *p = memory; int *end = memory + n - 2; // last valid start position while (p < end) { if (*(p + 1) == *p + 1 && *(p + 2) == *p + 2) { return (int)(p - memory); // pointer → index } p++; // move pointer } 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