Submission #289586

#	Time	Username	Problem	Language	Result	Execution time	Memory
289586		stoyan_malinin	Rail (IOI14_rail)	C++14	30 / 100	141 ms	98552 KiB

rail

#include "rail.h"
//#include "grader.cpp"

#include <set>
#include <vector>
#include <cstring>
#include <iostream>
#include <algorithm>
#include <functional>

using namespace std;

const int MAXN = 5005;

int askedAlready[MAXN][MAXN];
int ask(int x, int y)
{
    if(x>y) swap(x, y);
    if(askedAlready[x][y]==-1) askedAlready[x][y] = getDistance(x, y);

    return askedAlready[x][y];
}

int loc[MAXN];
set <int> allPositions[5];

int solveCase1(int l, int r, int k)
{
    int posK = loc[l] + ask(l, k);
    int posP = (loc[r] + posK - ask(r, k))/2;
    if((loc[r] + posK - ask(r, k))%2!=0) return -1;

    if(posP<=loc[r] && allPositions[1].count(posP)==true && posK<loc[r]) return posK;
    return -1;
}

int solveCase2(int l, int r, int k)
{
    int posK = loc[l] + ask(l, k);
    int posP = (loc[r] + posK - ask(r, k))/2;
    if((loc[r] + posK - ask(r, k))%2!=0) return -1;

    //cout << posP << '\n';

    if(posP<=loc[r] && allPositions[1].count(posP)==true && posK>loc[r]) return posK;
    return -1;
}

int solveCase3(int l, int r, int k)
{
    int posK = loc[r] - ask(r, k);
    int posP = (loc[l] + posK + ask(l, k))/2;

    if(posP>=loc[l] && allPositions[2].count(posP)==true && posK<loc[l]) return posK;
    return -1;
}

int solveCase4(int l, int r, int k)
{
    int posK = loc[r] - ask(r, k);
    int posP = (loc[l] + posK + ask(l, k))/2;

   // cout << posP << '\n';

    if(posP>=loc[l] && allPositions[2].count(posP)==true && posK>loc[l]) return posK;
    return -1;
}

void findLocation(int N, int first, int location[], int stype[])
{
    memset(askedAlready, -1, sizeof(askedAlready));

    vector <int> order;
    for(int i = 1;i<N;i++) order.push_back(i);
    sort(order.begin(), order.end(),
    [&](int a, int b)
    {
        if(ask(0, a)<ask(0, b)) return true;
        return false;
    });

    int l = 0;
    loc[0] = first;
    stype[0] = 1;
    allPositions[1].insert(loc[l]);

    int r = order[0];
    loc[ order[0] ] = first + ask(0, order[0]);
    stype[ order[0] ] = 2;
    allPositions[2].insert(loc[r]);

    for(int iter = 1;iter<order.size();iter++)
    {
        int val = -1;
        //cout << order[iter] << " || " << l << " " << r << '\n';

        val = solveCase1(l, r, order[iter]);
        if(val!=-1)
        {
            //cout << "CASE 1" << '\n';

            loc[ order[iter] ] = val;
            stype[ order[iter] ] = 2;

            allPositions[ stype[ order[iter] ] ].insert(val);
            continue;
        }

        val = solveCase2(l, r, order[iter]);
        if(val!=-1)
        {
            //cout << "CASE 2" << '\n';

            loc[ order[iter] ] = val;
            stype[ order[iter] ] = 2;

            allPositions[ stype[ order[iter] ] ].insert(val);
            r = order[iter];
            continue;
        }

        val = solveCase3(l, r, order[iter]);
        if(val!=-1)
        {
            loc[ order[iter] ] = val;
            stype[ order[iter] ] = 1;

            allPositions[ stype[ order[iter] ] ].insert(val);
            l = order[iter];
            continue;
        }

        val = solveCase4(l, r, order[iter]);
        if(val!=-1)
        {
            loc[ order[iter] ] = val;
            stype[ order[iter] ] = 1;

            allPositions[ stype[ order[iter] ] ].insert(val);
            continue;
        }

        //cout << order[iter] << " -> FAK" << '\n';
    }

    for(int i = 0;i<N;i++)
    {
        location[i] = loc[i];
        //cout << i << " -> " << stype[i] << " " << location[i] << '\n';
    }
}

Compilation message (stderr)

rail.cpp: In function 'void findLocation(int, int, int*, int*)':
rail.cpp:92:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   92 |     for(int iter = 1;iter<order.size();iter++)
      |                      ~~~~^~~~~~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 22 / 22
• Subtask 3: 0 / 26
• Subtask 4: 0 / 44