Submission #1110719

#	Time	Username	Problem	Language	Result	Execution time	Memory
1110719		hungnt	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	488 ms	5576 KiB

skyscraper

#pragma GCC optimize("O3")
#include <bits/stdc++.h>
#define BIT(x, k) (((x) >> (k)) & 1)
#define on(x, k) ((x) ^ (1ll << (k)))
#define pii pair<int, int>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define ll long long
using namespace std;

const int N = 50002;

int n, m;
int a[N];
vector<int> adj[N];
ll dp[N];

signed main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0);cout.tie(0);
    #define TASK "TASK"
    if (fopen(TASK".INP", "r"))
    {
        freopen(TASK".INP", "r", stdin);
        freopen(TASK".OUT", "w", stdout);
    }
    cin >> n >> m;
    for(int i = 0, x; i < m; i++)
    {
        cin >> a[i] >> x;
        adj[a[i]].push_back(x);
    }
	priority_queue<pii, vector<pii>, greater<pii>> pq;
    memset(dp, 0x3f, sizeof dp);
    dp[a[0]] = 0;
    pq.push({0, a[0]});
    while(!pq.empty())
    {
        pii tmp = pq.top();pq.pop();
        int u = tmp.se;
        if(dp[u] != tmp.fi) continue;
        for(auto &step : adj[u])
        {
            int w = tmp.fi;
            for(int v = u + step; v < n; v += step)
            {
                if (dp[v] > ++w)
                {
                    dp[v] = w;
                    pq.push({dp[v], v});
                }
            }
            w = tmp.fi;
            for(int v = u - step; v >= 0; v -= step)
            {
                if (dp[v] > ++w)
                {
                    dp[v] = w;
                    pq.push({dp[v], v});
                }
            }
        }
    }
    if(dp[a[1]] < dp[n]) cout << dp[a[1]];
    else cout << -1;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:26:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   26 |         freopen(TASK".INP", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:27:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   27 |         freopen(TASK".OUT", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

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