Submission #602739

#	Time	Username	Problem	Language	Result	Execution time	Memory
602739		proma	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	0 / 100	3 ms	1108 KiB

skyscraper

#include <bits/stdc++.h>

#define int long long
#define see(x) cout<<#x<<"="<<x<<endl;
#define endl "\n"

using namespace std;

const int N = 30005;
const int INF = 1e18;

int n, m, b[N], p[N], d[N];
vector <pair <int, int>> g[N];
priority_queue <pair <int, int>> q;
map <int, vector <int>> mp;

int32_t main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
///*
    freopen("input.txt", "r", stdin);
    freopen("output.txt", "w", stdout);
//*/

    cin >> n >> m;

    for (int i = 0; i < m; i ++) {
        cin >> b[i] >> p[i];
        mp[b[i]].push_back(i);
    }

    for (int i = 0; i < m; i ++) {
        for (int j = b[i] + p[i]; j < n; j += p[i]) {
            for (auto k: mp[j]) {
                if (k == i) continue;
                if (abs(b[k] - b[i]) % p[i] == 0) g[i].push_back({k, abs(b[k] - b[i]) / p[i]});
            }
        }
        for (int j = b[i] - p[i]; j >= 0; j -= p[i]) {
            for (auto k: mp[j]) {
                if (k == i) continue;
                if (abs(b[k] - b[i]) % p[i] == 0) g[i].push_back({k, abs(b[k] - b[i]) / p[i]});
            }
        }

    }

    for (int i = 0; i < m; i ++) {
        d[i] = INF;
    }
    d[0] = 0;
    q.push({0, 0});
    while (!q.empty()) {
        int v = q.top().second;
        q.pop();
        for (auto i: g[v]) {
            if (d[i.first] > d[v] + i.second) {
                d[i.first] = d[v] + i.second;
                q.push({-d[i.first], i.first});
            }
        }
    }

    if (d[1] == INF) d[1] = -1;
    cout << d[1] << endl;

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int32_t main()':
skyscraper.cpp:21:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |     freopen("input.txt", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:22:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   22 |     freopen("output.txt", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~

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