"""
 search.py
 
 Look for a number in a list.

"""

def search(x, items):
    """ Return position where x is in items. If not found return -1 """
    for i in range(len(items)):
        #print(i, items[i])
        if x == items[i]:
            return i
    # Didn't find it.
    return -1

print("Searching for 4 in [100, 10, 4, 3, 15]")
answer = search(4, [100, 10, 4, 3, 15])
print("answer is ", answer)

print("Searching for 17 in [100, 10, 4, 3, 15]")
answer = search(17, [100, 10, 4, 3, 15])
print("answer is ", answer)

def binary_search(x, low_index, high_index, items):
    """ search assuming items are in order """
    # using this binary half each time
    print(f" binary search: x={x}, low={low_index}, hi={high_index}, items={items}")
    if low_index > high_index:
        return -1
    else:
        middle_index = (low_index + high_index) // 2
        item = items[middle_index]
        if x == item:
            return middle_index
        elif x < item:
            return binary_search(x, low_index, middle_index - 1, items)
        elif x > item:
            return binary_search(x, middle_index + 1, high_index, items)
    
def search2(x, items):
    """ start binary search """
    return binary_search(x, 0, len(items) - 1, items)

print("Searching binary for 4 in [1, 2, 4, 20, 60, 100]")
answer = search2(4, [1, 2, 4, 20, 60, 100])
print("answer is ", answer)

print("Searching binary for 17 in [1, 2, 4, 20, 60, 100]")
answer = search2(17, [1, 2, 4, 20, 60, 100])
print("answer is ", answer)