Submission #993849


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// tsukasa_diary's programing contest code template
#include <bits/stdc++.h>
using namespace std;
#define TSUKASA_DIARY_S_TEMPLATE
// define
#define for_(i,a,b) for(int i=(a);i<(b);++i)
#define for_rev(i,a,b) for(int i=(a);i>=(b);--i)
#define allof(a) (a).begin(),(a).end()
#define minit(a,b) memset(a,b,sizeof(a))
#define size_of(a) int((a).size())
#define cauto const auto
// typedef
typedef long long lint;
typedef double Double;
typedef pair< int, int > pii;
template< typename T > using Vec = vector< T >;
template< typename T > using Matrix = Vec< Vec< T > >;
template< typename T > using USet = unordered_set< T >;
template< typename T, class C > using MyUSet = unordered_set< T, C >;
template< typename T, typename F > using UMap = unordered_map< T, F >;
template< typename T, typename F, class C > using MyUMap = unordered_map< T, F, C >;
// hash
class PiiHash { public: size_t operator () (const pii& p) const { return (p.first << 16) | p.second; } };
// popcount
inline int POPCNT(int x) { return __builtin_popcount(x); }
inline int POPCNT(lint x) { return __builtin_popcount(x); }
// inf
const int iINF = 1L << 30;
const lint lINF = 1LL << 60;
// eps
const Double EPS = 1e-9;
const Double PI = acos(-1);
// inrange
template< typename T >
inline bool in_range(T v, T mi, T mx) { return mi <= v && v < mx; }
template< typename T >
inline bool in_range(T x, T y, T W, T H) { return in_range(x,0,W) && in_range(y,0,H); }
// neighbor clockwise
const int DX[4] = {0,1,0,-1}, DY[4] = {-1,0,1,0};
const int DX_[8] = {0,1,1,1,0,-1,-1,-1}, DY_[8] = {-1,-1,0,1,1,1,0,-1};
// variable update
template< typename T > inline void modAdd(T& a, T b, T mod) { a = (a + b) % mod; }
template< typename T > inline void modMul(T& a, T b, T mod) { a = (a * b) % mod; }
template< typename T > inline void minUpdate(T& a, T b) { a = min(a, b); }
template< typename T > inline void maxUpdate(T& a, T b) { a = max(a, b); }
// converter
template< typename F, typename T >
inline void convert(F& from, T& to) {
	stringstream ss;
	ss << from; ss >> to;
}


int N, M, X[100010];
const int MAX_X = 100000;

void solve() {
	Vec< int > cnt(MAX_X + 1, 0);
	for_(i,0,N) cnt[X[i]]++;
	
	Vec< queue< int > > vque(M + 1);
	Vec< int > cnt_odd(M + 1);
	for_rev(x,MAX_X,1) if (cnt[x] > 0) {
		if (cnt[x] % 2) {
			vque[x % M].push(cnt[x] - 1);
			++cnt_odd[x % M];
		} else {
			vque[x % M].push(cnt[x]);
		}
	}
	
	int ans = 0;
	for_(x,0,M) {
		int a = x, b = (M - a) % M;
		
		if (a == b) {
			ans += cnt_odd[a] / 2;
		} else {
			ans += min(cnt_odd[a], cnt_odd[b]);
		}
		
		while (!vque[x].empty()) {
			int top = vque[x].front(); vque[x].pop();
			ans += top / 2;
		}
	}
	
	cout << ans << endl;
}

int main() {
	cin >> N >> M;
	for_(i,0,N) cin >> X[i];
	solve();
}




Submission Info

Submission Time
Task D - Pair Cards
User tsukasa_diary
Language C++14 (GCC 5.4.1)
Score 0
Code Size 2842 Byte
Status
Exec Time 119 ms
Memory 68608 KB

Judge Result

Set Name Score / Max Score Test Cases
sample 0 / 0 sample-01.txt, sample-02.txt
all 0 / 700 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
Case Name Status Exec Time Memory
01-01.txt 3 ms 640 KB
01-02.txt 31 ms 1280 KB
01-03.txt 31 ms 1280 KB
01-04.txt 31 ms 1280 KB
01-05.txt 31 ms 1280 KB
01-06.txt 31 ms 1280 KB
01-07.txt 31 ms 1280 KB
01-08.txt 32 ms 1408 KB
01-09.txt 32 ms 2432 KB
01-10.txt 64 ms 28160 KB
01-11.txt 116 ms 68608 KB
01-12.txt 30 ms 1024 KB
01-13.txt 67 ms 30592 KB
01-14.txt 31 ms 1408 KB
01-15.txt 31 ms 1408 KB
01-16.txt 31 ms 1536 KB
01-17.txt 31 ms 1664 KB
01-18.txt 34 ms 2944 KB
01-19.txt 42 ms 9344 KB
01-20.txt 119 ms 68608 KB
01-21.txt 30 ms 1024 KB
01-22.txt 30 ms 1024 KB
01-23.txt 30 ms 1024 KB
01-24.txt 31 ms 1920 KB
01-25.txt 55 ms 21504 KB
01-26.txt 112 ms 68608 KB
01-27.txt 103 ms 68352 KB
01-28.txt 87 ms 68224 KB
01-29.txt 36 ms 27264 KB
01-30.txt 85 ms 68224 KB
sample-01.txt 3 ms 640 KB
sample-02.txt 3 ms 640 KB