B. Ehab Is an Odd Person

Links: https://codeforces.com/contest/1174/problem/B

Meaning of the questions:

You're given an array aa of length nn. You can perform the following operation on it as many times as you want:

• Pick two integers ii and jj (1≤i,j≤n)(1≤i,j≤n) such that ai+ajai+aj is odd, then swap aiai and ajaj.

What is lexicographically the smallest array you can obtain?

An array xx is lexicographically smaller than an array yy if there exists an index ii such that xi<yixi<yi, and xj=yjxj=yj for all 1≤j<i1≤j<i. Less formally, at the first index ii in which they differ, xi<yi

Ideas:

Record the number of even and odd, as long as the even and odd arrays simultaneously, regardless of the array can make several completely sorted.

Code:

#include <bits/stdc++.h>

using namespace std;

typedef long long LL;
const int MAXN = 3e5 + 10;
const int MOD = 1e9 + 7;
int n, m, k, t;

int a[MAXN];

int main()
{
    cin >> n;
    bool flag1 = false, flag2 = false;
    for (int i = 1;i <= n;i++)
    {
        cin >> a[i];
        if (a[i] % 2 == 0)
            flag1 = true;
        if (a[i] % 2 == 1)
            flag2 = true;
    }
    if (flag1 && flag2)
        sort(a+1, a+1+n);
    for (int i = 1;i <= n;i++)
        cout << a[i] << ' ';
    cout << endl;

    return 0;
}