Educational Codeforces Round 35 D - Inversion Counting

#include<iostream>
#include<algorithm>
#include<iomanip>
#include<cstdio>
#include<cstdlib>
#include<cstring>
#include<string>
#include<cmath>
#include<set>
#include<queue>
#include<stack>
#include<map>
#define PI acos(-1.0)
#define in freopen("in.txt", "r", stdin)
#define out freopen("out.txt", "w", stdout)
#define kuaidian ios::sync_with_stdio(0);

using namespace std;
typedef long long ll;
typedef unsigned long long ull;
const int maxn = 1500 + 7, maxd = 1e5 + 7;
const ll mod = 1e9 + 7;
const int INF = 0x7f7f7f7f;

int n, m, l_, r_;
int a[maxn], vis[maxn];
int ans = 0;

int main() {

scanf("%d", &n);
for(int i = 1; i <= n; ++i) {
scanf("%d", &a[i]);
}

scanf("%d", &m);
for(int i = 0; i < m; ++i) {
scanf("%d %d", &l_, &r_);
for(int j = l_, k = r_; j <= k; ++j, --k) {
swap(a[j], a[k]);
}

memset(vis, 0, sizeof vis);
ans = n;

for(int i = 1; i <= n; ++i) {
if(vis[i] == 0) {
ans--;
vis[i] = 1;
int p = a[i];
while(vis[p] == 0) {
vis[p] = 1;
p = a[p];
}
}
}

printf("%s\n", (ans % 2 == 0 ? "even" : "odd") );
}

return 0;
}