下面两个程序在#4全部MLE，求助

from numpy import *

maxn = 1073741824
n = zeros((maxn,),dtype=uint32)
s = input().split(' ')
n0 = set()
for i in input().split(' '):
    x = int(i)
    n[x] += 1
    n0.add(x)
c = int(s[1])
ans = 0
for i in n0:
    if i+c<maxn:
        ans += n[i]*n[i+c]
print(ans)

from numpy import *

maxn = 1073741824
n = zeros((maxn,),dtype=uint32)
s = input().split(' ')
n0 = []
c = int(s[1])
for i in input().split(' '):
    x = int(i)
    n[x] += 1
    if x>=c:
        n0.append(x-c)
ans = 0
for i in n0:
    ans += n[i]
print(ans)

第一个程序在#3还WA，为什么？