Submission #6141578

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Source Code Expand

from collections import Counter
n,m=map(int,input().split())
x=[int(i) for i in input().split()]
v=[[] for i in range(m)]
for i in x:v[i%m].append(i)
a=0
for i in range(1,m//2+1*(m%2==1)):
  x,y=v[i],v[m-i]
  d=len(x)-len(y)
  if d<0:
    d=-d
    x,y=y,x
  c=sorted(Counter(x).items(),key=lambda x:x[1])
  p=0
  for t in c:
    p+=(t[1]//2)
  a+=len(y)+min(p,(d//2))
a+=len(v[0])//2+(len(v[m//2])//2 if m%2==0 else 0)
print(a)

Submission Info

Judge Result