Submission #652040

#	Time	Username	Problem	Language	Result	Execution time	Memory
652040		TimDee	Flight to the Ford (BOI22_communication)	C++17	15 / 100	7379 ms	35268 KiB

communication

#include"communication.h"
#include <bits/stdc++.h>
using namespace std;
#define forn(i,n) for (int i=0; i<n; ++i)
#pragma GCC optimize("O3")
#pragma GCC optimize("Ofast")

vector<int> V;
void brut(int x, int n, int v=0, int i=0, int l=0) {
    if (i>=n) {V.push_back(v); return;}
    int b=(x>>i)&1;
    brut(x,n,v+(b<<i),i+1,0);
    if (l==0) brut(x,n,v+((!b)<<i),i+1,1);
}

vector<int> get_possible(int n) {
    int x=0, q=0;
    forn(i,29) {
        q=receive();
        x+=q<<i;
    }
    brut(x,29,0,0,0);
    vector<int> b;
    for (auto x:V) {
        if (x>=n) continue;
        for (int i=0; i+x<n; i+=1<<29) {
            b.push_back(x);
        }
    }
    V.clear();
    return b;
}

vector<int> dequery(vector<int>&a,int bit) {
    int x=0, q;
    forn(i,bit) x+=receive()<<i;
    brut(x,bit);

    vector<int> b;
    for (auto x:V) {
        if (x>=a.size()) continue;
        for (int i=0; i+x<a.size(); i+=(1<<bit)) {
            b.push_back(a[i+x]);
        }
    }
    V.clear();
    return b;

}

pair<int,int> decode(int n) {
    
    vector<int> a=get_possible(n); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=dequery(a,21);
    a=dequery(a,15);
    a=dequery(a,11);
    a=dequery(a,8);
    a=dequery(a,6);
    a=dequery(a,4);
    a=dequery(a,3);

    a=dequery(a,4); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=dequery(a,3); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=dequery(a,2); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=dequery(a,2); //for (auto x:a) cout<<x<<' '; cout<<'\n';

    if (a.size()==1) return{a[0]+1,a[0]+1};
    if (a.size()==2) return{a[0]+1,a[1]+1};
    assert(a.size()==3);

    int q,x=0;
    q=receive();
    x+=q<<0;
    q=receive();
    x+=q<<1;
    q=receive();
    x+=q<<2;
    q=receive();
    x+=q<<3;

    vector<int> ans;
    vector<int> A={0,1,5,10,9,8,2,4};
    vector<int> B={1,8,9,11,13,3,12,0};
    vector<int> C={6,15,2,4,12,3,7,14};
    for (auto v:A) if (v==x) ans.push_back(a[0]);
    for (auto v:B) if (v==x) ans.push_back(a[2]);
    for (auto v:C) if (v==x) ans.push_back(a[1]);

    if (ans.size()==1) return {ans[0]+1,ans[0]+1};
    return {ans[0]+1,ans[1]+1};

}

int Send(int x, int bit) {
    int ret=0;
    forn(i,bit) ret+=send((x>>i)&1)<<i;
    return ret;
}

vector<int> get_possible(int n, int x) {
    x=Send(x,29);
	brut(x,29);
	vector<int> b;
	for (auto x:V) {
        if (x>=n) continue;
        for (int i=0; i+x<n; i+=1<<29) {
            b.push_back(x);
        }
    }
	V.clear();
	return b;
}

vector<int> query(vector<int>&a,int x,int bit) {
	int r=0;
    while (a[r]!=x) if (r>=a.size()) exit(1); else ++r;
    r=Send(r,bit);
	brut(r,bit);
	vector<int> b;
	for (auto x:V) {
		if (x>=a.size()) continue;
		for (int i=0; i+x<a.size(); i+=(1<<bit)) {
			b.push_back(a[i+x]);
		}
	}
	V.clear();
	return b;

}

void encode(int n, int x) {

	--x;
    vector<int> a=get_possible(n,x); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=query(a,x,21);
    a=query(a,x,15);
    a=query(a,x,11);
    a=query(a,x,8);
    a=query(a,x,6);
    a=query(a,x,4);
    a=query(a,x,3);

    a=query(a,x,4); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=query(a,x,3); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=query(a,x,2); //for (auto x:a) cout<<x<<' '; cout<<'\n';
    a=query(a,x,2); //for (auto x:a) cout<<x<<' '; cout<<'\n';

    if (a.size()<3) return;

    assert(a.size()==3);
    int v=0,b=0;;
    if (x==a[0]) {
        b=send(0);
        v+=b<<0;
        b=send(0);
        v+=b<<1;
        b=send(0);
        v+=b<<2;
        b=send(0);
        v+=b<<3;
    } else if (x==a[1]) {
        b=send(0);
        v+=b<<0;
        b=send(1);
        v+=b<<1;
        b=send(1);
        v+=b<<2;
        b=send(0);
        v+=b<<3;
    } else {
        b=send(1);
        v+=b<<0;
        b=send(0);
        v+=b<<1;
        b=send(0);
        v+=b<<2;
        b=send(1);
        v+=b<<3;
    }
    
}

Compilation message (stderr)

communication.cpp: In function 'std::vector<int> dequery(std::vector<int>&, int)':
communication.cpp:41:14: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   41 |         if (x>=a.size()) continue;
      |             ~^~~~~~~~~~
communication.cpp:42:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   42 |         for (int i=0; i+x<a.size(); i+=(1<<bit)) {
      |                       ~~~^~~~~~~~~
communication.cpp:35:14: warning: unused variable 'q' [-Wunused-variable]
   35 |     int x=0, q;
      |              ^
communication.cpp: In function 'std::vector<int> query(std::vector<int>&, int, int)':
communication.cpp:116:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  116 |     while (a[r]!=x) if (r>=a.size()) exit(1); else ++r;
      |                         ~^~~~~~~~~~
communication.cpp:121:8: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  121 |   if (x>=a.size()) continue;
      |       ~^~~~~~~~~~
communication.cpp:122:20: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  122 |   for (int i=0; i+x<a.size(); i+=(1<<bit)) {
      |                 ~~~^~~~~~~~~

• Subtask 1: 15 / 15
• Subtask 2: 0 / 85