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give 2 ascending sorted arrays with same length n, find the nth number between these 2 arrays
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#!/usr/bin/python | |
def get_nth_num(a, b): | |
if len(a) != len(b) or len(a) == 0: | |
return None | |
id_a, id_b = 0, 0 | |
for _ in xrange(len(a)): | |
if a[id_a] <= b[id_b]: | |
tmp = a[id_a] | |
id_a += 1 | |
else: | |
tmp = b[id_b] | |
id_b += 1 | |
return tmp | |
def get_nth_num_fast_(a, left_a, right_a, b, left_b, right_b): | |
if right_a == left_a: | |
return a[left_a] < b[left_b] and a[left_a] or b[left_b] | |
mid_a = (left_a + right_a) / 2 | |
mid_b = (left_b + right_b) / 2 | |
if (right_a - left_a + 1) % 2 == 0: | |
if a[mid_a] < b[mid_b]: | |
return get_nth_num_fast_(a, mid_a + 1, right_a, b, left_b, mid_b) | |
else: | |
return get_nth_num_fast_(a, left_a, mid_a, b, mid_b + 1, right_b) | |
else: | |
if a[mid_a] < b[mid_b]: | |
return get_nth_num_fast_(a, mid_a, right_a, b, left_b, mid_b) | |
else: | |
return get_nth_num_fast_(a, left_a, mid_a, b, mid_b, right_b) | |
def get_nth_num_fast(a, b): | |
if len(a) != len(b) or len(a) == 0: | |
return None | |
return get_nth_num_fast_(a, 0, len(a) - 1, b, 0, len(b) - 1) | |
def main(): | |
a = [1, 5, 8, 90, 100, 101] | |
b = [2, 6, 8, 10, 23, 45] | |
print get_nth_num(a, b) | |
print get_nth_num_fast(a, b) | |
a = [1, 5, 8, 9, 15, 21, 32] | |
b = [2, 6, 8, 10, 23, 45, 46] | |
print get_nth_num(a, b) | |
print get_nth_num_fast(a, b) | |
if __name__ == '__main__': | |
main() |
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