제출 #339676

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
339676		blue	Jakarta Skyscrapers (APIO15_skyscraper)	C++11	100 / 100	342 ms	64560 KiB

skyscraper

#include <iostream>
#include <set>
#include <vector>
#include <set>
using namespace std;

/*
If P[i] < √N, there are at most √N distinct values of i.
If P[i] > √N, i has edges to at most √N positions.
*/
vector<int> mindist(30000, 1e9);

struct distcomp
{
    int x;
};

bool operator < (distcomp A, distcomp B)
{
    if(mindist[A.x] == mindist[B.x]) return A.x < B.x;
    return mindist[A.x] < mindist[B.x];
}

int main()
{
    int N, M;
    cin >> N >> M;

    int pos0, pos1;

    set<int> doges[N];
    vector<int> edge[N];
    vector<int> dist[N];

    int B, P;
    for(int i = 0; i < M; i++)
    {
        cin >> B >> P;
        if(i == 0) pos0 = B;
        if(i == 1) pos1 = B;
        doges[B].insert(P);
    }

    for(int pos = 0; pos < N; pos++)
    {
        for(int jump: doges[pos])
        {
            for(int x = pos + jump; x < N; x += jump)
            {
                edge[pos].push_back(x);
                dist[pos].push_back((x - pos)/jump);
                if(doges[x].find(jump) != doges[x].end()) break;
            }

            for(int x = pos - jump; x >= 0; x -= jump)
            {
                edge[pos].push_back(x);
                dist[pos].push_back((pos - x)/jump);
                if(doges[x].find(jump) != doges[x].end()) break;
            }
        }
    }

    set<distcomp> S;
    mindist[pos0] = 0;
    for(int i = 0; i < N; i++) S.insert(distcomp{i});

    int u, v, w;
    while(!S.empty())
    {
        u = S.begin()->x;
        S.erase(S.begin());

        for(int i = 0; i < edge[u].size(); i++)
        {
            v = edge[u][i];
            w = dist[u][i];

            if(mindist[v] > mindist[u] + w)
            {
                S.erase(distcomp{v});
                mindist[v] = mindist[u] + w;
                S.insert(distcomp{v});
            }
        }
    }

    // for(int i = 0; i < N; i++)
    // {
    //     cout << i << ' ' << mindist[i] << ": ";
    //     for(int j = 0; j < edge[i].size(); j++) cout << edge[i][j] << ' ' << dist[i][j] << " | ";
    //     cout << '\n';
    // }
    //
    //
    // cout << pos1 << ' ' << mindist[pos1] << '\n';

    if(mindist[pos1] == 1e9) cout << "-1\n";
    else cout << mindist[pos1] << '\n';
}

컴파일 시 표준 에러 (stderr) 메시지

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:74:26: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   74 |         for(int i = 0; i < edge[u].size(); i++)
      |                        ~~^~~~~~~~~~~~~~~~
skyscraper.cpp:65:17: warning: 'pos0' may be used uninitialized in this function [-Wmaybe-uninitialized]
   65 |     mindist[pos0] = 0;
      |                 ^
skyscraper.cpp:98:20: warning: 'pos1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   98 |     if(mindist[pos1] == 1e9) cout << "-1\n";
      |                    ^

• Subtask 1: 10 / 10
• Subtask 2: 12 / 12
• Subtask 3: 14 / 14
• Subtask 4: 21 / 21
• Subtask 5: 43 / 43