import time
import random
import searching

def make_list(n):
    '''Return a random list of n elements.'''
    
    res = range(n)
    random.shuffle(res)
    return res

def time_search(f, L, n):
    '''Return how many seconds it takes to run searching function f on a
    list with n random ints and a random search key.'''
    
    t1 = time.time()
    ans = f(L, n)
    t2 = time.time()
    return t2 - t1
    
def time_index(L,n):
    '''Return how many seconds it takes to run list.index on a list with
    n random ints, and a random search key.'''
    
    t1 = time.time()
    ans = L.index(n)
    t2 = time.time()
    return t2 - t1

def make_sorted_list(n):
    '''Return a random sorted list of n elements.  There may be duplicates.
    Values in the list will be between 0 and 100 times the len of list.'''
    
    res = []
    for i in range(n):
        res[i] = random.randint(0, n*100)
    sort(res)
    return res
        
def time_binary_search(n):
    '''Return how many seconds it takes to run binary search on a
    sorted list with n random ints and a random search key.'''
    
    L = range(n)
    t1 = time.time()
    ans = searching.binary_search(L, random.randint(0, n))
    t2 = time.time()
    return t2 - t1
        
        
if __name__ == "__main__":
    
    for size in [4000, 8000, 32000, 1024000]:
        L = make_list(size)
        n = random.randint(0, size)
        print "==", size, "=="
        s = time_search(searching.search, L,n)
        print "search:", s
        ss = time_search(searching.sentinel_search, L,n)        
        print "sentinel search:", ss
        bs = time_binary_search(size)
        print "binary search:",bs
        ti = time_index(L,n)
        print "list.index:", ti        
        print "simple search is:"
        print "  %f times slower than sentinel search" % (s/ss)
        print "  %f times slower than list.index" % (s/ti)                 
        print "comparison with binary search is not fair, since",
        print "binary search knows its list is sorted"