Submission #946134

#	Time	Username	Problem	Language	Result	Execution time	Memory
946134		GrindMachine	Question (Grader is different from the original contest) (CEOI14_question_grader)	C++17	100 / 100	2234 ms	24960 KiB

encoder

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

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
edi

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int B = 12;

int encode(int n, int x, int y) {
    vector<int> fact(B+5);
    fact[0] = 1;
    rep1(i,B) fact[i] = fact[i-1]*i;

    auto ncr = [&](int n_, int r){
        if(n_ < r) return 0;
        return fact[n_]/(fact[r]*fact[n_-r]);
    };

    auto get = [&](int k){
        int need = B/2;
        int mask = 0;

        rev(i,B-1,0){
            int b = 0;
            if(need){
                if(k > ncr(i,need)){
                    k -= ncr(i,need);
                    b = 1;
                }
            }

            need -= b;
            mask = (mask<<1)|b;
        }

        assert(!need);
        assert(k == 1);
        return mask;
    };

    int mask1 = get(x);
    int mask2 = get(y);

    rep(bit,B){
        int f = 1<<bit;
        if((mask1&f) and !(mask2&f)){
            return bit+1;
        }
    }

    assert(0);
    return -1;
}

decoder

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

using namespace std;
using namespace __gnu_pbds;

template<typename T> using Tree = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update>;
typedef long long int ll;
typedef long double ld;
typedef pair<int,int> pii;
typedef pair<ll,ll> pll;

#define fastio ios_base::sync_with_stdio(false); cin.tie(NULL)
#define pb push_back
#define endl '\n'
#define sz(a) (int)a.size()
#define setbits(x) __builtin_popcountll(x)
#define ff first
#define ss second
#define conts continue
#define ceil2(x,y) ((x+y-1)/(y))
#define all(a) a.begin(), a.end()
#define rall(a) a.rbegin(), a.rend()
#define yes cout << "Yes" << endl
#define no cout << "No" << endl

#define rep(i,n) for(int i = 0; i < n; ++i)
#define rep1(i,n) for(int i = 1; i <= n; ++i)
#define rev(i,s,e) for(int i = s; i >= e; --i)
#define trav(i,a) for(auto &i : a)

template<typename T>
void amin(T &a, T b) {
    a = min(a,b);
}

template<typename T>
void amax(T &a, T b) {
    a = max(a,b);
}

#ifdef LOCAL
#include "debug.h"
#else
#define debug(x) 42
#endif

/*

refs:
edi

*/

const int MOD = 1e9 + 7;
const int N = 1e5 + 5;
const int inf1 = int(1e9) + 5;
const ll inf2 = ll(1e18) + 5;
const int B = 12;

int decode(int n, int q, int h) {
    vector<int> fact(B+5);
    fact[0] = 1;
    rep1(i,B) fact[i] = fact[i-1]*i;

    auto ncr = [&](int n_, int r){
        if(n_ < r) return 0;
        return fact[n_]/(fact[r]*fact[n_-r]);
    };

    auto get = [&](int k){
        int need = B/2;
        int mask = 0;

        rev(i,B-1,0){
            int b = 0;
            if(need){
                if(k > ncr(i,need)){
                    k -= ncr(i,need);
                    b = 1;
                }
            }

            need -= b;
            mask = (mask<<1)|b;
        }

        assert(!need);
        assert(k == 1);
        return mask;
    };

    int mask = get(q);
    int f = 1<<(h-1);
    return ((mask&f) > 0);
}

• Subtask 1: 100 / 100