Submission #828201

#	Time	Username	Problem	Language	Result	Execution time	Memory
828201		GrindMachine	Prisoner Challenge (IOI22_prison)	C++17	0 / 100	1 ms	212 KiB

prison

// Om Namah Shivaya

#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 ff first
#define ss second
#define all(a) a.begin(),a.end()
#define rall(a) a.rbegin(),a.rend()
#define conts continue
#define sz(a) a.size()

#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 &x, T y){
  x = min(x,y);
}

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

#define debug(x) cout << #x << " = "; cout << x; cout << endl

/*

refs:
https://youtu.be/RwrBLp8AvJA
edi

*/

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

#include "prison.h"

int pos_bit(int x, int b, int p){
    rep(i,p){
        x /= b;
    }
    return x%b;
}

std::vector<std::vector<int>> devise_strategy(int n) {
    int base = 2;
    int LOG = 0;
    while(pow(base,LOG+1) <= n) LOG++;
    LOG++;

    vector<vector<int>> a(LOG*base-2,vector<int>(n+1));
    int curr_bit = LOG;
    int know_who = 1;

    rep(i,sz(a)){
        if(i == 0){
            a[i][0] = 0;
            rep1(j,n){
                int b = pos_bit(j,base,LOG-1);
                a[i][j] = i+b+1;
            }
            conts;
        }

        if((i-1)%base == 0){
            curr_bit--;
            know_who ^= 1;
        }

        a[i][0] = know_who^1;
        int b1 = (i-1)%base;
        if(!curr_bit) b1++;
        int nxt = ((i-1)/base+1)*base+1;

        rep1(j,n){
            int b2 = pos_bit(j,base,curr_bit);
            if(b1 < b2){
                a[i][j] = -(know_who+1);
            }
            else if(b2 < b1){
                a[i][j] = -((know_who^1)+1);
            }
            else{
                // check next bit, go to appropriate state
                if(curr_bit){
                    int nxt_bit = pos_bit(j,base,curr_bit-1);
                    if(curr_bit > 1){
                        a[i][j] = nxt+nxt_bit;
                    }
                    else{
                        if(nxt_bit == 0){
                            a[i][j] = -((know_who^1)+1);
                        }
                        else if(nxt_bit == base-1){
                            a[i][j] = -(know_who+1);
                        }
                        else{
                            a[i][j] = nxt+nxt_bit+1;
                        }
                    }
                }
            }
        }
    }

    // rep(i,sz(a)){
    //     rep(j,n+1){
    //         cout << a[i][j] << " ";
    //     }
    //     cout << endl;
    // }

    return a;
}

Compilation message (stderr)

prison.cpp: In function 'std::vector<std::vector<int> > devise_strategy(int)':
prison.cpp:26:35: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::vector<int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   26 | #define rep(i,n) for(int i = 0; i < n; ++i)
      |                                   ^
prison.cpp:75:5: note: in expansion of macro 'rep'
   75 |     rep(i,sz(a)){
      |     ^~~

• Subtask 1: 0 / 5
• Subtask 2: 0 / 5
• Subtask 3: 0 / 90