답안 #160461

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
160461 2019-10-27T14:13:28 Z Benq Cat (info1cup19_cat) C++14
51.25 / 100
580 ms 14348 KB
#pragma GCC optimize ("O3")
#pragma GCC target ("sse4")

#include <bits/stdc++.h>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/rope>

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;
 
typedef long long ll;
typedef long double ld;
typedef complex<ld> cd;

typedef pair<int, int> pi;
typedef pair<ll,ll> pl;
typedef pair<ld,ld> pd;

typedef vector<int> vi;
typedef vector<ld> vd;
typedef vector<ll> vl;
typedef vector<pi> vpi;
typedef vector<pl> vpl;
typedef vector<cd> vcd;

template <class T> using Tree = tree<T, null_type, less<T>, rb_tree_tag,tree_order_statistics_node_update>;

#define FOR(i, a, b) for (int i = (a); i < (b); i++)
#define F0R(i, a) for (int i = 0; i < (a); i++)
#define FORd(i,a,b) for (int i = (b)-1; i >= (a); i--)
#define F0Rd(i,a) for (int i = (a)-1; i >= 0; i--)
#define trav(a, x) for (auto& a : x)

#define mp make_pair
#define pb push_back
#define f first
#define s second
#define lb lower_bound
#define ub upper_bound

#define sz(x) (int)x.size()
#define all(x) begin(x), end(x)
#define rsz resize

const int MOD = 1000000007; // 998244353
const ll INF = 1e18;
const int MX = 200005;
const ld PI = 4*atan((ld)1);

template<class T> void ckmin(T &a, T b) { a = min(a, b); }
template<class T> void ckmax(T &a, T b) { a = max(a, b); }

namespace input {
    template<class T> void re(complex<T>& x);
    template<class T1, class T2> void re(pair<T1,T2>& p);
    template<class T> void re(vector<T>& a);
    template<class T, size_t SZ> void re(array<T,SZ>& a);

    template<class T> void re(T& x) { cin >> x; }
    void re(double& x) { string t; re(t); x = stod(t); }
    void re(ld& x) { string t; re(t); x = stold(t); }
    template<class Arg, class... Args> void re(Arg& first, Args&... rest) { 
        re(first); re(rest...); 
    }

    template<class T> void re(complex<T>& x) { T a,b; re(a,b); x = cd(a,b); }
    template<class T1, class T2> void re(pair<T1,T2>& p) { re(p.f,p.s); }
    template<class T> void re(vector<T>& a) { F0R(i,sz(a)) re(a[i]); }
    template<class T, size_t SZ> void re(array<T,SZ>& a) { F0R(i,SZ) re(a[i]); }
}

using namespace input;

namespace output {
    template<class T1, class T2> void pr(const pair<T1,T2>& x);
    template<class T, size_t SZ> void pr(const array<T,SZ>& x);
    template<class T> void pr(const vector<T>& x);
    template<class T> void pr(const set<T>& x);
    template<class T1, class T2> void pr(const map<T1,T2>& x);

    template<class T> void pr(const T& x) { cout << x; }
    template<class Arg, class... Args> void pr(const Arg& first, const Args&... rest) { 
        pr(first); pr(rest...); 
    }

    template<class T1, class T2> void pr(const pair<T1,T2>& x) { 
        pr("{",x.f,", ",x.s,"}"); 
    }
    template<class T> void prContain(const T& x) {
        pr("{");
        bool fst = 1; for (const auto& a: x) pr(!fst?", ":"",a), fst = 0; // const needed for vector<bool>
        pr("}");
    }
    template<class T, size_t SZ> void pr(const array<T,SZ>& x) { prContain(x); }
    template<class T> void pr(const vector<T>& x) { prContain(x); }
    template<class T> void pr(const set<T>& x) { prContain(x); }
    template<class T1, class T2> void pr(const map<T1,T2>& x) { prContain(x); }
    
    void ps() { pr("\n"); }
    template<class Arg> void ps(const Arg& first) { 
        pr(first); ps(); // no space at end of line
    }
    template<class Arg, class... Args> void ps(const Arg& first, const Args&... rest) { 
        pr(first," "); ps(rest...); // print w/ spaces
    }
}

using namespace output;

namespace io {
    void setIn(string s) { freopen(s.c_str(),"r",stdin); }
    void setOut(string s) { freopen(s.c_str(),"w",stdout); }
    void setIO(string s = "") {
        ios_base::sync_with_stdio(0); cin.tie(0); // fast I/O
        if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
    }
}

using namespace io;

template<class T> T invGeneral(T a, T b) {
    a %= b; if (a == 0) return b == 1 ? 0 : -1;
    T x = invGeneral(b,a); 
    return x == -1 ? -1 : ((1-(ll)b*x)/a+b)%b;
}

template<class T> struct modular {
    T val; 
    explicit operator T() const { return val; }
    modular() { val = 0; }
    modular(const ll& v) { 
        val = (-MOD <= v && v <= MOD) ? v : v % MOD;
        if (val < 0) val += MOD;
    }
    
    friend ostream& operator<<(ostream& os, const modular& a) { return os << a.val; }
    friend bool operator==(const modular& a, const modular& b) { return a.val == b.val; }
    friend bool operator!=(const modular& a, const modular& b) { return !(a == b); }
    friend bool operator<(const modular& a, const modular& b) { return a.val < b.val; }

    modular operator-() const { return modular(-val); }
    modular& operator+=(const modular& m) { if ((val += m.val) >= MOD) val -= MOD; return *this; }
    modular& operator-=(const modular& m) { if ((val -= m.val) < 0) val += MOD; return *this; }
    modular& operator*=(const modular& m) { val = (ll)val*m.val%MOD; return *this; }
    friend modular pow(modular a, ll p) {
        modular ans = 1; for (; p; p /= 2, a *= a) if (p&1) ans *= a;
        return ans;
    }
    friend modular inv(const modular& a) { 
        auto i = invGeneral(a.val,MOD); assert(i != -1);
        return i;
    } // equivalent to return exp(b,MOD-2) if MOD is prime
    modular& operator/=(const modular& m) { return (*this) *= inv(m); }
    
    friend modular operator+(modular a, const modular& b) { return a += b; }
    friend modular operator-(modular a, const modular& b) { return a -= b; }
    friend modular operator*(modular a, const modular& b) { return a *= b; }
    
    friend modular operator/(modular a, const modular& b) { return a /= b; }
};

typedef modular<int> mi;
typedef pair<mi,mi> pmi;
typedef vector<mi> vmi;
typedef vector<pmi> vpmi;

mt19937 rng(chrono::steady_clock::now().time_since_epoch().count());

vpi v;
int N;
vpi ans;

void mov(int a, int b, int c) {
	if (c == 0) {
		ans.pb({a+1,b+1});
		swap(v[a],v[b]);
	} else {
		ans.pb({a+1,N-b});
		swap(v[a],v[b]);
		v[a].s ^= 1, v[b].s ^= 1;
	}
}

void solve() {
	v.clear(); ans.clear();
	re(N); vi a(N); re(a);
	trav(t,a) t --;
	F0R(i,N/2) if (a[i]+a[N-1-i] != N-1) {
		ps(-1);
		return;
	}
	F0R(i,N/2) v.pb({min(a[i],a[N-1-i]),a[i] > a[N-1-i]});
	F0R(i,N/2) while (v[i].f != i) {
		if (v[i].s && v[v[i].f].s) mov(i,v[i].f,1);
		else mov(i,v[i].f,0);
	}
	vi bad;
	F0R(i,sz(v)) if (v[i].s) bad.pb(i);
	if (sz(bad)&1) {
		ps(-1);
		return;
	}
	while (sz(bad) > 1) {
		mov(bad[sz(bad)-2],bad[sz(bad)-1],0);
		mov(bad[sz(bad)-2],bad[sz(bad)-1],1);
		bad.pop_back();
		bad.pop_back();
	}
	// ps(v);
	ps(sz(ans),sz(ans));
	trav(t,ans) ps(t.f,t.s);
}

int main() {
    setIO();
    int T; re(T);
    F0R(i,T) solve();
}

/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?), set tle
    * do smth instead of nothing and stay organized
*/

Compilation message

cat.cpp: In function 'void io::setIn(std::__cxx11::string)':
cat.cpp:113:35: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setIn(string s) { freopen(s.c_str(),"r",stdin); }
                            ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
cat.cpp: In function 'void io::setOut(std::__cxx11::string)':
cat.cpp:114:36: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     void setOut(string s) { freopen(s.c_str(),"w",stdout); }
                             ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~
# 결과 실행 시간 메모리 Grader output
1 Partially correct 7 ms 376 KB Valid reconstruction
# 결과 실행 시간 메모리 Grader output
1 Correct 25 ms 504 KB Output is correct
2 Correct 24 ms 504 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Partially correct 7 ms 376 KB Valid reconstruction
2 Correct 25 ms 504 KB Output is correct
3 Correct 24 ms 504 KB Output is correct
4 Partially correct 28 ms 632 KB Valid reconstruction
5 Partially correct 12 ms 504 KB Valid reconstruction
6 Partially correct 10 ms 376 KB Valid reconstruction
# 결과 실행 시간 메모리 Grader output
1 Correct 25 ms 504 KB Output is correct
2 Correct 24 ms 504 KB Output is correct
3 Correct 509 ms 10304 KB Output is correct
4 Correct 496 ms 9888 KB Output is correct
5 Correct 528 ms 12228 KB Output is correct
# 결과 실행 시간 메모리 Grader output
1 Partially correct 7 ms 376 KB Valid reconstruction
2 Correct 25 ms 504 KB Output is correct
3 Correct 24 ms 504 KB Output is correct
4 Partially correct 28 ms 632 KB Valid reconstruction
5 Partially correct 12 ms 504 KB Valid reconstruction
6 Partially correct 10 ms 376 KB Valid reconstruction
7 Correct 509 ms 10304 KB Output is correct
8 Correct 496 ms 9888 KB Output is correct
9 Correct 528 ms 12228 KB Output is correct
10 Partially correct 540 ms 11160 KB Valid reconstruction
11 Partially correct 504 ms 9132 KB Valid reconstruction
12 Partially correct 551 ms 12236 KB Valid reconstruction
13 Partially correct 580 ms 14348 KB Valid reconstruction
14 Partially correct 527 ms 12404 KB Valid reconstruction