#include <stdio.h> int find_pattern(int *mem, int n) { if(n < 3) {return -1;} for(int i = 2; i < n; i++){ int val1 = *(mem + i - 2); int val2 = *(mem + i - 1); int val3 = *(mem + i); if((val2 == val1 + 1) && (val3 == val2 + 1)){ return (i - 2); } } 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