Submission #4673616

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Source Code Expand

#include <bits/stdc++.h>
// #pragma GCC optimize ("O3")
// #pragma GCC target ("sse4")
using namespace std;

typedef long long LL;
typedef unsigned long long ULL;
typedef pair<int,int> PII;

#define REP(i,n) for(int i=0;i<(n);++i)
#define FOR(i,a,b) for (int i=(a); i<(b); ++i)
#define FORD(i,a,b) for (int i=(a)-1; i>=(b); --i)

#define pb push_back
#define mp make_pair
#define st first
#define nd second

const int MOD = 1000000007;

int A[211111];

int main() {
  // ios_base::sync_with_stdio(0);

  int N, M;
  scanf("%d%d", &N, &M);
  N *= 2;
  REP(i,N) {
    scanf("%d", &A[i]);
  }
  sort(A, A+N);
  int S = 0;
  FORD(i,N,0) {
    int K = lower_bound(A, A+N, M-A[i]) - A;
    S = max(S, K - (N-1-i));
  }
  S += S % 2;

  int Z = 0;
  REP(i,S) Z = max(Z, A[i] + A[S-1-i]);
  FOR(i,S,N) Z = max(Z, A[i] + A[N-1-(i-S)] - M);
  printf("%d\n", Z);
}

Submission Info

Compile Error

./Main.cpp: In function ‘int main()’:
./Main.cpp:27:24: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d", &N, &M);
                        ^
./Main.cpp:30:23: warning: ignoring return value of ‘int scanf(const char*, ...)’, declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d", &A[i]);
                       ^

Judge Result