Submission #877406

#	Time	Username	Problem	Language	Result	Execution time	Memory
877406		boris_mihov	Fun Tour (APIO20_fun)	C++17	0 / 100	4 ms	9052 KiB

fun

#include "fun.h"
#include <algorithm>
#include <iostream>
#include <cassert>
#include <numeric>
#include <vector>
#include <queue>

typedef long long llong;
const int MAXN = 100000 + 10;
const int INF  = 1e9;

int n;
int sz[MAXN];
int pos[MAXN];
int type[MAXN];
int perm[MAXN];
int depth[MAXN];
std::vector <int> g[MAXN];
int waitlistType = -1;

void calcSize(int node, int par)
{
    sz[node] = 1;
    for (const int &u : g[node])
    {
        if (u == par)
        {
            continue;
        }

        calcSize(u, node);
        sz[node] += sz[u];
    }
}

int findCentroid(int node, int par)
{
    for (const int &u : g[node])
    {
        if (u != par && sz[u] > n / 2)
        {
            return findCentroid(u, node);
        }
    }

    return node;
}

void assign(int node, int par, int t)
{
    type[node] = t;
    depth[node] = depth[par] + 1;
    for (const int &u : g[node])
    {
        if (u == par)
        {
            continue;
        }

        assign(u, node, t);
    }
}

std::vector <int> createFunTour(int N, int Q) 
{  
    n = N;
    for (int i = 1 ; i <= n ; ++i)
    {
        for (int j = 2 ; j <= n ; ++j)
        {
            if (hoursRequired(i - 1, j - 1) == 1)
            {
                g[i].push_back(j);
                g[j].push_back(i);
            }
        }
    }

    calcSize(1, 0);
    int cntr = findCentroid(1, 0);

    for (int idx = 0 ; idx < g[cntr].size() ; ++idx)
    {
        assign(g[cntr][idx], cntr, idx);
    }

    std::iota(perm + 1, perm + 1 + n, 1);
    std::sort(perm + 1, perm + 1 + n, [&](int x, int y)
    {
        return type[x] < type[y] || (type[x] == type[y] && depth[x] > depth[y]);
    });

    std::iota(pos + 1, pos + 1 + n, 0);
    std::sort(pos + 1, pos + 1 + n, [&](int x, int y)
    {
        if ((x & 1) != (y & 1)) return (x & 1) < (y & 1);
        return x < y;
    });

    std::vector <int> answer(n);
    for (int i = 1 ; i <= n ; ++i)
    {
        answer[pos[i]] = perm[i] - 1;
    }

    for (int i = 1 ; i < n ; ++i)
    {
        assert(type[answer[i] + 1] != type[answer[i - 1] + 1]);
    }

    for (int i = 1 ; i < n - 1 ; ++i)
    {
        while (depth[answer[i - 1] + 1] + depth[answer[i] + 1] < depth[answer[i + 1] + 1] + depth[answer[i] + 1]);
    }

    return answer;
}

Compilation message (stderr)

fun.cpp: In function 'std::vector<int> createFunTour(int, int)':
fun.cpp:83:28: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   83 |     for (int idx = 0 ; idx < g[cntr].size() ; ++idx)
      |                        ~~~~^~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 0 / 16
• Subtask 3: 0 / 21
• Subtask 4: 0 / 19
• Subtask 5: 0 / 34