Contest Duration: ~ (local time) (180 minutes)

Submission #7913601

Source Code Expand

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```import sys
from collections import Counter

N, M = map(int, input().split())
X = list(map(int, input().split()))

def main():
P = [[] for _ in range(M)]

for x in X:
P[x%M].append(x)

ans = 0
checked = [False]*M
for m in range(M):
if checked[m]:
continue
if m == 0:
C1 = Counter(P[m])
for num, c in C1.items():
ans += c//2
else:
L1, L2 = len(P[m]), len(P[M-m])
if L1 > L2:
ans += L2
C1 = Counter(P[m])
n = 0
for num, c1 in C1.items():
if c1 % 2 != 0:
n += 1
if L2 >= n:
ans += (L1-L2)//2
else:
ans += (L1-n)//2
else:
ans += L1
C2 = Counter(P[M-m])
n = 0
for num, c2 in C2.items():
if c2 % 2 != 0:
n += 1
if L1 >= n:
ans += (L2-L1)//2
else:
ans += (L1-n)//2
checked[m] = True
checked[M-m] = True

print(ans)

if __name__ == "__main__":
main()```

#### Submission Info

Submission Time 2019-10-09 10:47:38+0900 D - Pair Cards wattaihei Python (3.4.3) 0 1356 Byte WA 416 ms 19876 KB

#### Judge Result

Set Name sample all
Score / Max Score 0 / 0 0 / 700
Status
Test Cases sample-01.txt, sample-02.txt sample-01.txt, sample-02.txt, 01-01.txt, 01-02.txt, 01-03.txt, 01-04.txt, 01-05.txt, 01-06.txt, 01-07.txt, 01-08.txt, 01-09.txt, 01-10.txt, 01-11.txt, 01-12.txt, 01-13.txt, 01-14.txt, 01-15.txt, 01-16.txt, 01-17.txt, 01-18.txt, 01-19.txt, 01-20.txt, 01-21.txt, 01-22.txt, 01-23.txt, 01-24.txt, 01-25.txt, 01-26.txt, 01-27.txt, 01-28.txt, 01-29.txt, 01-30.txt, sample-01.txt, sample-02.txt
Set Name Test Cases
sample sample-01.txt, sample-02.txt
all sample-01.txt, sample-02.txt, 01-01.txt, 01-02.txt, 01-03.txt, 01-04.txt, 01-05.txt, 01-06.txt, 01-07.txt, 01-08.txt, 01-09.txt, 01-10.txt, 01-11.txt, 01-12.txt, 01-13.txt, 01-14.txt, 01-15.txt, 01-16.txt, 01-17.txt, 01-18.txt, 01-19.txt, 01-20.txt, 01-21.txt, 01-22.txt, 01-23.txt, 01-24.txt, 01-25.txt, 01-26.txt, 01-27.txt, 01-28.txt, 01-29.txt, 01-30.txt, sample-01.txt, sample-02.txt
Case Name Status Exec Time Memory
01-01.txt 21 ms 3316 KB
01-02.txt 73 ms 15652 KB
01-03.txt 74 ms 14132 KB
01-04.txt 67 ms 14132 KB
01-05.txt 71 ms 14132 KB
01-06.txt 66 ms 14132 KB
01-07.txt 65 ms 14132 KB
01-08.txt 69 ms 14132 KB
01-09.txt 77 ms 14132 KB
01-10.txt 210 ms 14132 KB
01-11.txt 408 ms 18212 KB
01-12.txt 63 ms 13656 KB
01-13.txt 196 ms 13656 KB
01-14.txt 77 ms 18080 KB
01-15.txt 66 ms 14132 KB
01-16.txt 68 ms 14132 KB
01-17.txt 69 ms 14132 KB
01-18.txt 78 ms 14132 KB
01-19.txt 111 ms 14132 KB
01-20.txt 416 ms 19876 KB
01-21.txt 65 ms 14132 KB
01-22.txt 61 ms 14132 KB
01-23.txt 62 ms 14132 KB
01-24.txt 70 ms 14132 KB
01-25.txt 162 ms 14132 KB
01-26.txt 368 ms 16420 KB
01-27.txt 370 ms 15536 KB
01-28.txt 323 ms 11544 KB
01-29.txt 143 ms 6616 KB
01-30.txt 320 ms 11332 KB
sample-01.txt 20 ms 3316 KB
sample-02.txt 21 ms 3316 KB