Submission #992403

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Source Code Expand

#include <bits/stdc++.h>
using namespace std;


int main()
{
  int n,m;
  scanf("%d%d",&n,&m);
  vector<vector<int> > X(m);
  for(int i=0;i<n;i++){
    int x;
    scanf("%d",&x);
    X[x%m].push_back(x);
  }
  vector<int> K(m);
  for(int i=0;i<m;i++){
    sort(X[i].begin(),X[i].end());
    K[i]=0;
    for(int j=0;j<X[i].size();j++){
      if(j+1<X[i].size()&&X[i][j]==X[i][j+1]){
	K[i]++;
	j++;
      }
    }
  }
  int C=0;
  for(int i=0;2*i<=m;i++){
    if(i==0||2*i==m){
      C+=X[i].size()/2;
    }
    else{
      if(X[i].size()>=X[m-i].size()){
	C+=X[m-i].size();
	C+=min((int)(X[i].size()-X[m-i].size())/2,K[i]);
      }
      else{
	C+=X[i].size();
	C+=min((int)(X[m-i].size()-X[i].size())/2,K[m-i]);
      }
    }
  }
  printf("%d\n",C);
  return 0;
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:8:22: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d",&n,&m);
                      ^
./Main.cpp:12:19: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d",&x);
                   ^

Judge Result