Submission #46529

#	Time	Username	Problem	Language	Result	Execution time	Memory
46529		RayaBurong25_1	Rail (IOI14_rail)	C++17	100 / 100	243 ms	99152 KiB

rail

#include "rail.h"
#include <set>
#include <cassert>
#define INF 1000000007
int Dist[5005][5005];
bool operator<(std::pair<int, int> a, std::pair<int, int> b)
{
    return (a.first < b.first || (a.first == b.first && a.second < b.second));
}
void findLocation(int N, int first, int location[], int stype[])
{
    int i, j;
    for (i = 0; i < N; i++)
    {
        for (j = 0; j < N; j++)
        {
            if (i == j)
                Dist[i][j] = 0;
            else
                Dist[i][j] = -1;
        }
    }
    location[0] = first;
    stype[0] = 1;
    int u, ud = INF;
    for (i = 0; i < N; i++)
    {
        if (Dist[0][i] == -1)
        {
            Dist[0][i] = getDistance(0, i);
            Dist[i][0] = Dist[0][i];
            if (Dist[0][i] < ud)
            {
                u = i;
                ud = Dist[0][i];
            }
        }
    }
    if (ud == INF)
        return;
    location[u] = first + ud;
    stype[u] = 2;
    for (i = 0; i < N; i++)
    {
        if (Dist[u][i] == -1)
        {
            Dist[u][i] = getDistance(u, i);
            Dist[i][u] = Dist[u][i];
            if (Dist[u][i] < Dist[u][0] && Dist[u][i] == Dist[0][i] - Dist[0][u])
            {
                location[i] = location[u] - Dist[u][i];
                stype[i] = 1;
            }
        }
    }
    // for (i = 0; i < N; i++)
    //     printf("i%d #%d %d\n", i, stype[i], location[i]);
    // printf("u%d\n", u);
    int v, d;
    std::set<std::pair<int, int> > M;
    std::set<int> C;
    M.clear();
    C.clear();
    v = 0;
    C.insert(location[0]);
    for (i = 0; i < N; i++)
    {
        if (stype[i] != 0) continue;
        if (Dist[0][i] != Dist[0][u] + Dist[u][i]) continue;
        M.insert({Dist[u][i], i});
    }
    std::set<std::pair<int, int> >::iterator it;
    for (it = M.begin(); it != M.end(); it++)
    {
        if (Dist[v][it->second] == -1)
        {
            Dist[v][it->second] = getDistance(v, it->second);
            Dist[it->second][v] = Dist[v][it->second];
        }
        d = (Dist[u][v] + Dist[v][it->second] - Dist[u][it->second])/2;
        // printf("it (%d %d) d %d -> find %d\n", it->first, it->second, d, location[v] + d);
        if (C.find(location[v] + d) != C.end())
        {
            location[it->second] = location[v] + Dist[v][it->second];
            stype[it->second] = 2;
        }
        else
        {
            location[it->second] = location[u] - Dist[u][it->second];
            stype[it->second] = 1;
            C.insert(location[it->second]);
            v = it->second;
        }
    }
    // for (i = 0; i < N; i++)
    //     printf("i%d #%d %d\n", i, stype[i], location[i]);
    M.clear();
    C.clear();
    v = u;
    C.insert(location[u]);
    for (i = 0; i < N; i++)
    {
        if (stype[i] != 0) continue;
        M.insert({Dist[0][i], i});
    }
    for (it = M.begin(); it != M.end(); it++)
    {
        if (Dist[v][it->second] == -1)
        {
            Dist[v][it->second] = getDistance(v, it->second);
            Dist[it->second][v] = Dist[v][it->second];
        }
        d = (Dist[0][v] + Dist[v][it->second] - Dist[0][it->second])/2;
        if (C.find(location[v] - d) != C.end())
        {
            location[it->second] = location[v] - Dist[v][it->second];
            stype[it->second] = 1;
        }
        else
        {
            location[it->second] = location[0] + Dist[0][it->second];
            stype[it->second] = 2;
            C.insert(location[it->second]);
            v = it->second;
        }
    }
    for (i = 0; i < N; i++)
        assert(stype[i] != 0);
    // for (i = 0; i < N; i++)
    //     printf("i%d #%d %d\n", i, stype[i], location[i]);
}

Compilation message (stderr)

rail.cpp: In function 'void findLocation(int, int, int*, int*)':
rail.cpp:80:23: warning: 'u' may be used uninitialized in this function [-Wmaybe-uninitialized]
         d = (Dist[u][v] + Dist[v][it->second] - Dist[u][it->second])/2;
              ~~~~~~~~~^

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