Submission #249711

#	Time	Username	Problem	Language	Result	Execution time	Memory
249711		receed	Jakarta Skyscrapers (APIO15_skyscraper)	C++14	100 / 100	301 ms	50040 KiB

skyscraper

#include <iostream>
#include <iomanip>
#include <cstdio>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cstring>
#include <cassert>
#include <string>
#include <set>
#include <map>
#include <random>
#include <bitset>
#include <string>
#include <unordered_set>
#include <unordered_map>
#include <deque>
#include <queue>
#define rep(i, n) for (int i = 0; i < (n); i++)
#define all(x) (x).begin(), (x).end()
#define rall(x) (x).rbegin(), (x).rend()

using namespace std;
using ll = long long;
using ul = unsigned long long;
using ld = long double;

const int N = 30001, M = 7500000;
map<pair<int, int>, vector<int>> li;
vector<int> g[N];
bitset<M> nx, pr;
short num[M];
int d[M];
bitset<M> used;

void adde(int u, int v, bool w) {
    g[u].push_back(v * 2 + w);
}

int main() {
    ios_base::sync_with_stdio(0); cin.tie(0);
    int n, m, cb, cp, s, t;
    cin >> n >> m;
    rep(i, m) {
        cin >> cb >> cp;
        if (i == 0)
            s = cb;
        else if (i == 1)
            t = cb;
        li[{cp, cb % cp}].push_back(cb);
    }
    int cs = n;
    for (auto &pp : li) {
        auto p = pp.first;
        int ck = (n - p.second + p.first - 1) / p.first;
        rep(i, ck - 1) {
            nx[cs + i] = 1;
            pr[cs + i + 1] = 1;
        }
        rep(i, ck)
            num[cs + i] = p.second + i * p.first;
        for (int i : pp.second)
            adde(i, cs + (i - p.second) / p.first, 0);
        cs += ck;
        assert(cs < M);
    }
    deque<int> q {s};
    rep(i, cs)
        d[i] = M;
    d[s] = 0;
    while (!q.empty()) {
        int v = q.front();
        q.pop_front();
        if (used[v])
            continue;
        used[v] = 1;
        if (v < n)
            for (int p : g[v]) {
                int u = p / 2;
                if (p % 2) {
                    if (d[u] > d[v] + 1) {
                        d[u] = d[v] + 1;
                        q.push_back(u);
                    }
                }
                else if (d[u] > d[v]) {
                    d[u] = d[v];
                    q.push_front(u);
                }
            }
        else {
            if (nx[v] && d[v + 1] > d[v] + 1) {
                d[v + 1] = d[v] + 1;
                q.push_back(v + 1);
            }
            if (pr[v] && d[v - 1] > d[v] + 1) {
                d[v - 1] = d[v] + 1;
                q.push_back(v - 1);
            }
            if (d[num[v]] > d[v]) {
                d[num[v]] = d[v];
                q.push_front(num[v]);
            }
        }
    }
    if (d[t] == M)
        cout << -1;
    else
        cout << d[t];
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:106:12: warning: 't' may be used uninitialized in this function [-Wmaybe-uninitialized]
     if (d[t] == M)
         ~~~^
skyscraper.cpp:70:10: warning: 's' may be used uninitialized in this function [-Wmaybe-uninitialized]
     d[s] = 0;
     ~~~~~^~~

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