Submission #993130

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Source Code Expand

using System;
using System.Text;
using System.Collections.Generic;
class Solve{
    int N,M;
    int[] X;
    public Solve(){}
    StringBuilder sb;
    public static int Main(){
        new Solve().Run();
        return 0;
    }
    void Run(){
        sb = new StringBuilder();
        Read();
        Calc();
        Console.Write(sb.ToString());
    }
    void Calc(){
        int[] A = new int[100001];
        for(int i=0;i<100001;i++){
            A[i] = 0;
        }
        for(int i=0;i<N;i++){
            A[X[i]]++;
        }
        int[] B = new int[M];
        int[] C = new int[M];
        for(int i=0;i<M;i++){
            B[i] = 0;
            C[i] = 0;
        }
        for(int i=0;i<100001;i++){
            B[i%M] += A[i];
            if(A[i] % 2 == 0){
                C[i%M] += A[i];
            }
            else{
                C[i%M] += A[i] - 1;
            }
        }
        int count = 0;
        for(int i=0;i <= M-i;i++){
            if(i == M-i || i == 0){
                count += B[i]/2;
            }
            else{
                if(B[i] > B[M-i]){
                    count += B[M-i];
                    if(C[i] > B[i] - B[M-i]){
                        count += (B[i] - B[M-i])/2; 
                    }
                    else{
                        count += C[i]/2;
                    }
                }
                else{
                    count += B[i];
                    if(C[M-i] > B[M-i] - B[i]){
                        count += (B[M-i] - B[i])/2;
                    }
                    else{
                        count += C[M-i]/2;
                    }
                }
            }
        }
        sb.Append(count+"\n");
    }
    void Read(){
        string[] str = Console.ReadLine().Split(' ');
        N = int.Parse(str[0]);
        M = int.Parse(str[1]);
        X = new int[N];
        str = Console.ReadLine().Split(' ');
        for(int i=0;i<N;i++){
            X[i] = int.Parse(str[i]);
        }
    }    
}

Submission Info

Judge Result