1335A-Candies_and_two_sister.cpp

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

typedef long long ll;
typedef vector<int> vi;
typedef vector<ll> vl;
typedef vector<vi> vvi;
typedef vector<vl> vvl;
typedef pair<int, int> pii;
typedef pair<double, double> pdd;
typedef pair<ll, ll> pll;
typedef vector<pii> vii;
typedef vector<pll> vll;
typedef double dl;

#define endl '\n'
#define PB push_back
#define F first
#define S second
#define all(a) (a).begin(), (a).end()
#define rall(a) (a).rbegin(), (a).rend()
#define sz(x) (int)x.size()

const double PI = acos(-1);
const double eps = 1e-9;
const int inf = 2000000000;
const ll infLL = 9000000000000000000;
#define MOD 1000000007

#define mem(a, b) memset(a, b, sizeof(a))
#define sqr(a) ((a) * (a))

#define optimize()                \
    ios_base::sync_with_stdio(0); \
    cin.tie(0);                   \
    cout.tie(0);
#define fraction()                \
    cout.unsetf(ios::floatfield); \
    cout.precision(10);           \
    cout.setf(ios::fixed, ios::floatfield);
#define file()                        \
    freopen("input.txt", "r", stdin); \
    freopen("output.txt", "w", stdout);

#define dbg(args...)            \
    do                          \
    {                           \
        cerr << #args << " : "; \
        debug(args);            \
    } while (0)
void debug()
{
    cerr << endl;
}
template <typename T, typename... hello>
void debug(T arg, const hello &...rest)
{
    cerr << arg << ' ';
    debug(rest...);
}

ll gcd(ll a, ll b)
{
    return __gcd(a, b);
}
ll lcm(ll a, ll b)
{
    return a * (b / gcd(a, b));
}

int diff(int a, int b)
{
    return b - a;
}

int main()
{
    optimize();

    int t;
    cin>>t;
    while(t--)
    {
        int n;
        cin>>n;
        if(n<=2)
        {
            cout<<0<<endl;
        }
        else if(n%2==0)
        {
            cout<<(n/2)-1<<endl;
        }
        else
        {
            cout<<n/2<<endl;
        }
    }
    
    return 0;
}