NC222458. [USACOJan2021B]EvenMoreOddPhotos

描述

输入描述

The first line of input contains N. The next line contains N space-separated integers giving the breed IDs of the N cows.

输出描述

The maximum possible number of groups in Farmer John's photo. It can be shown that at least one feasible grouping exists.

示例1

输入:

7
1 3 5 7 9 11 13

输出:

3

说明:

In this example, one way to form the maximum number of three groups is as follows. Place 1 and 3 in the first group, 5, 7, and 9 in the second group, and 11 and 13 in the third group.

示例2

输入:

7
11 2 17 13 1 15 3

输出:

5

说明:

In this example, one way to form the maximum number of five groups is as follows. Place 2 in the first group, 11 in the second group, 13 and 1 in the third group, 15 in the fourth group, and 17 and 3 in the fifth group.

Problem credits: Nick Wu

原站题解

#include <iostream>
using namespace std;

int main(void) {
  int N, O = 0, E = 0;
  cin >> N;
  for (int i = 0, x; i < N; i++) {
    cin >> x;
    E += 1 ^ (x % 2), O += (x % 2);
    // if (x % 2 == 0)
    //   E++;
    // else
    //   O++;
  }
  while (O > E)
    O = O - 2, E++;

  E = min(E, O + 1);
  // if (E > O + 1)
  //   E = O + 1;
  cout << E + O << endl;
}