Python algorithm-quickly search for two numbers that meet the conditions

Python algorithm-to quickly find the two numbers that meet the condition, the premise is that such two numbers must exist.

I don't want to write about the solution.

At first, I thought of solution 2. the last hash table.

(Actually, I want to create an array as big as target .. if the index exists, it is written to the index, but to find all the data, the two-dimensional array is required. However, if the target is large, is it a waste of space... so change to Dict)

Only two numbers are required for the question --

More interesting expansion problems

It should not be difficult to find three, but it is unclear about others. I would like to add more...

1. two-dimensional array

def find_pair(A, target):    B = [[] for i in range(target + 1)]    for i in range(0, len(A)):        if A[i] <= target:            B[A[i]].append(i)    for i in range(0, target / 2 + 1):        if len(B[i]) != 0 and len(B[target - i]) != 0:            print(i, B[i], target-i, B[target-i])  if __name__ == "__main__":    A = [0, 1, 1, 2, 11, 8, 3, 4, 5, 6, 7, 8, 9, 10]    find_pair(A, 9)

2. dictionary

def find_pair(A, target):    B = {}    for i in range(0, len(A)):        if A[i] <= target:            if not B.has_key(A[i]):                B[A[i]] = [i]            else:                B[A[i]].append(i)    for i in range(0, target / 2 + 1):        if B.has_key(i) and B.has_key(target-i):            print(i, B[i], target-i, B[target-i])  if __name__ == "__main__":    A = [0, 1, 1, 2, 11, 8, 3, 4, 5, 6, 7, 8, 9, 10]    find_pair(A, 9)

3. this method has been re-sorted, and I don't know what the meaning of the index returned in the book is... the sorting is lazy and the built-in...

def find_pair(A, target):    A.sort()    i, j = 0, len(A) - 1    while i < j:        s = A[i] + A[j]        if s == target:            print(i, A[i], j, A[j])            i += 1            j -= 1        elif s < target:            i += 1        else:            j -= 1  if __name__ == "__main__":    A = [0, 1, 1, 2, 11, 8, 3, 4, 5, 6, 7, 8, 9, 10]    find_pair(A, 9)