Codeforces Round #485 (Div. 1) B. Petr and Permutations 思维

B. Petr and Permutations

input

5
2 4 5 1 3

output

Petr

code

//Siberian Squirrel
#include<bits/stdc++.h>

#define IO ios::sync_with_stdio(false);cin.tie(0);cout.tie(0)
#define ACM_LOCAL

using namespace std;
typedef long long ll;

const int INF = 0x3f3f3f3f;
const int N = 2e6 + 10;
const int MOD = 998244353;

ll n, m, k, w, res = 0;
int f[N], a[N], q[N], t[N];

ll quick_pow(ll ans, ll p, ll res = 1) {
    
    
    for(; p; p >>= 1, ans = ans * ans % MOD)
        if(p & 1) res = res * ans % MOD;
    return res % MOD;
}

ll inv(ll ans) {
    
    
    return quick_pow(ans, MOD - 2);
}

ll C(int n, int m) {
    
    
    if(n < m || n <= 0 || m < 0) return 0;
    if(m == 0) return 1;
    return 1ll * f[n] * inv(f[m]) % MOD * inv(f[n - m]) % MOD;
}

void merge_sort(int l, int r) {
    
    
    if(l >= r) return;
    int mid = l + r >> 1;
    merge_sort(l, mid), merge_sort(mid + 1, r);
    int k = 0, i = l, j = mid + 1;
    while(i <= mid && j <= r) {
    
    
        if(q[i] <= q[j]) t[k ++] = q[i ++];
        else {
    
    
            t[k ++] = q[j ++];
            res += mid - i + 1;
        }
    }
    while(i <= mid) t[k ++] = q[i ++];
    while(j <= r) t[k ++] = q[j ++];
    for(i = l, j = 0; i <= r; ++ i, ++ j) q[i] =t[j];
}

inline void solve(ll ans = 0) {
    
    
    if((abs(((n % 2) - (res % 2)))) & 1) cout << "Um_nik\n";
    else cout << "Petr\n";
}

int main() {
    
    
    IO;
#ifdef ACM_LOCAL
    freopen("input.txt", "r", stdin);
	freopen("output.txt", "w", stdout);
#endif
	f[0] = f[1] = 1;
	for(int i = 2; i < N; ++ i) f[i] = 1ll * f[i - 1] * i % MOD;
    int o = 1;
//    cin >> o;
    while(o --) {
    
    
        cin >> n;
        for(int i = 0; i < n; ++ i) cin >> q[i];
        merge_sort(0, n - 1);
        solve();
    }

    return 0;
}