#include <stdio.h>
#include <stdint.h>
int binary_search(uint8_t *arr, uint8_t n, uint8_t key) {
int low = 0;
int high = n-1;
int found = 0;
while(low<=high){
int mid = low + (high - low)/2;
if(key == arr[mid]){
return mid;
found = 1;
break;
}
else if(key > arr[mid]){
low = mid + 1;
}
else if(key < arr[mid]){
high = mid - 1;
}
}
if(!found){
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