#include <stdio.h>
#include <stdint.h>
int binary_search(uint8_t *arr, uint8_t n, uint8_t key) {
// Your logic here
int arr_mid = n/2;
int mid = arr_mid;
do {
if (arr[mid] == key) {
return mid;
}
if (key < arr[mid]) {
mid = mid / 2;
}
else if (key > arr[mid]) {
mid = mid + (n-mid) / 2;
}
} while (arr_mid != mid && mid != 0 && mid != n-1);
if (arr[mid] == key) {
return mid;
}
return -1;
}
int main() {
uint8_t n, key;
scanf("%hhu", &n);
uint8_t arr[100];
for (uint8_t i = 0; i < n; i++) {
scanf("%hhu", &arr[i]);
}
scanf("%hhu", &key);
int index = binary_search(arr, n, key);
printf("%d", index);
return 0;
}
Input
6 5 10 15 20 25 30 20
Expected Output
3