Submission #870612

#	Time	Username	Problem	Language	Result	Execution time	Memory
870612		anha3k25cvp	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	131 ms	65708 KiB

skyscraper

#include <bits/stdc++.h>
#define ll long long
#define ull unsigned long long
#define dl double
#define st first
#define nd second
#define II pair <int, int>

using namespace std;

const int N = 5 + 1e5;
const int inf = 7 + 1e9;

int n, m;
vector <int> b, p;

namespace subtask5 {
    void main() {
        vector <set <int>> g(n);
        for (int i = 1; i <= m; i ++)
            g[b[i]].insert(p[i]);
        vector <vector <II>> adj(n);
        for (int i = 0; i < n; i ++)
            for (int val : g[i]) {
                for (int j = 1; j * val <= i; j ++) {
                    adj[i].push_back({i - j * val, j});
                    if (g[i - j * val].count(val))
                        break;
                }
                for (int j = 1; i + j * val < n; j ++) {
                    adj[i].push_back({i + j * val, j});
                    if (g[i + j * val].count(val))
                        break;
                }
            }
        vector <int> f(n, inf);
        priority_queue <II> q;
        q.push({-(f[b[1]] = 0), b[1]});
        while (!q.empty()) {
            int du = -q.top().st, u = q.top().nd;
            q.pop();
            if (f[u] < du)
                continue;
            if (u == b[2]) {
                cout << du;
                return;
            }
            for (auto z : adj[u]) {
                int v = z.st, w = z.nd;
                if (du + w < f[v])
                    q.push({-(f[v] = du + w), v});
            }
        }
        cout << -1;
    }
}

int main() {
#define TASKNAME ""
    ios_base :: sync_with_stdio (0);
    cin.tie (0);
    if ( fopen( TASKNAME".inp", "r" ) ) {
        freopen (TASKNAME".inp", "r", stdin);
        freopen (TASKNAME".out", "w", stdout);
    }
    cin >> n >> m;
    b.assign(m + 1, 0);
    p.assign(m + 1, 0);
    for (int i = 1; i <= m; i ++)
        cin >> b[i] >> p[i];
    subtask5 :: main();
    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:63:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   63 |         freopen (TASKNAME".inp", "r", stdin);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:64:17: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   64 |         freopen (TASKNAME".out", "w", stdout);
      |         ~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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