Submission #31244

#	Time	Username	Problem	Language	Result	Execution time	Memory
31244		nibnalin	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	0 / 100	0 ms	4372 KiB

skyscraper

#include <iostream>
#include <cstdio>
#include <vector>
#include <set>
#include <cmath>
#include <algorithm>
using namespace std;

const int inf = int(1e9)+5, maxn = int(3e4)+5;

int D[maxn][2];
vector<pair<int, int>> A;
vector<int> graph[maxn];
set<pair<int, int>> doge[maxn];

// 0 => doge
// 1 => skyscraper

bool go(int x, int y)
{
	if(A[x].first == y) return 1;
    auto it = doge[y].lower_bound({A[x].second, -1});
    return (it == doge[y].end() && it->first != A[x].second);
}

int main(void)
{
    int n, m;
    scanf("%d%d", &n, &m);
    A.clear(); A.resize(m);
    for(int i = 0;i < m;i++) scanf("%d%d", &A[i].first, &A[i].second), D[i][0] = inf;
	for(int i = 0;i < n;i++) D[i][1] = inf;
	
    sort(A.begin(), A.end());
    A.resize(int(unique(A.begin(), A.end())-A.begin()));
    m = int(A.size());

    for(int i = 0;i < m;i++)
    {
        doge[A[i].first].insert({A[i].second, i});
    }


    for(int i = 0;i < m;i++)
    {
        for(int j = A[i].first;j < n;j += A[i].second)
        {
            if(go(i, j)) graph[i].push_back(j);
            else
            {
            	graph[i].push_back(j);
            	break;
            }
        }

        for(int j = A[i].first;j >= 0;j -= A[i].second)
        {
            if(go(i, j)) graph[i].push_back(j);
            else
            {
            	graph[i].push_back(j);
            	break;
            }
        }
    }

    set<pair<int, pair<int, int>>> Q;
    Q.insert({0, {0, 0}});
    D[0][0] = 0;

    while(!Q.empty())
    {
        pair<int, pair<int, int>> top = *Q.begin();
        Q.erase(Q.begin());
        //cout << top.first << " " << top.second.first << " " << top.second.second << "\n";

        if(top.second.second)
        {
            for(auto it: doge[top.second.first])
            {
                if(D[it.second][0] > top.first)
                {
                    if(D[it.second][0] != inf) Q.erase({D[it.second][0], {it.second, 0}});
                    D[it.second][0] = top.first;
                    Q.insert({D[it.second][0], {it.second, 0}});
                }
            }
        }
        else
        {
            for(auto it: graph[top.second.first])
            {
                int c = top.first+abs(it-A[top.second.first].first)/A[top.second.first].second;
                if(D[it][1] > c)
                {
                    if(D[it][1] != inf) Q.erase({D[it][1], {it, 1}});
                    D[it][1] = c;
                    Q.insert({D[it][1], {it, 1}});
                }
            }
        }
    }
    printf("%d\n", (D[1][0] == inf)?-1:D[1][0]);
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:29:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d%d", &n, &m);
                          ^
skyscraper.cpp:31:85: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     for(int i = 0;i < m;i++) scanf("%d%d", &A[i].first, &A[i].second), D[i][0] = inf;
                                                                                     ^

• Subtask 1: 0 / 10
• Subtask 2: 0 / 12
• Subtask 3: 0 / 14
• Subtask 4: 0 / 21
• Subtask 5: 0 / 43