Submission #146600

#	Time	Username	Problem	Language	Result	Execution time	Memory
146600		karma	Jakarta Skyscrapers (APIO15_skyscraper)	C++11	100 / 100	243 ms	67816 KiB

skyscraper

#include <bits/stdc++.h>
#define Task     "test"
#define pb        emplace_back
#define mp        make_pair

using namespace std;

const int N = 30001;
const int Irene = int(1e9) + 7;
typedef pair<int, int> pii;

int n, m, u, dis, st, en, d[N];
set<int> jump[N];
vector<pii> a[N];
priority_queue<pii, vector<pii>, greater<pii>> pq;

void Enter()
{
     cin >> n >> m;
     for(int i = 0; i < m; ++i) {
        cin >> u >> dis;
        if(!i) st = u;
        else if(i == 1) en = u;
        jump[u].insert(dis);
     }
     for(int i = 0; i < n; ++i) {
        for(int len: jump[i]) {
            int irene = i, step = 0;
            while(++step, (irene -= len) >= 0) {
                a[i].pb(irene, step);
                if(jump[irene].find(len) != jump[irene].end()) break;
            }
            irene = i, step = 0;
            while(++step, (irene += len) < n) {
                a[i].pb(irene, step);
                if(jump[irene].find(len) != jump[irene].end()) break;
            }
        }
     }
}

void Solve()
{
     fill(d, d + n, Irene);
     d[st] = 0; pq.push(mp(0, st));
     int u, dis;
     while(pq.size()) {
        pii top = pq.top(); pq.pop();
        dis = top.first, u = top.second;
        if(dis != d[u]) continue;
        for(pii irene: a[u]) {
            int Dis = irene.second + d[u];
            if(Dis < d[irene.first]) d[irene.first] = Dis, pq.push(mp(Dis, irene.first));
        }
     }
     if(d[en] == Irene) cout << -1;
     else cout << d[en];
}

int main()
{
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    if(fopen(Task".inp", "r")) {
        freopen(Task".inp", "r", stdin);
        freopen(Task".out", "w", stdout);
    }

    Enter(), Solve();

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:65:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         freopen(Task".inp", "r", stdin);
         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:66:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
         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