Submission #1192764

#	Time	Username	Problem	Language	Result	Execution time	Memory
1192764		Gray	Jakarta Skyscrapers (APIO15_skyscraper)	C++20	0 / 100	162 ms	327680 KiB

skyscraper

#include <algorithm>
#include <bits/stdc++.h>
#include <cassert>
#include <vector>
using namespace std;
#define ll long long
#define ull unsigned long long
#define ld long double
#define ff first
#define ss second
#define ln "\n"
#define mp make_pair
#define pb push_back
#define INF (ll)1e18
ll MOD = 1e9+7;

struct Fenwick{
    vector<ll> pref, suff;
    ll n, offs;
    Fenwick(ll N){
        n=N+20; offs=10;;
        pref.resize(n+1);
        suff.resize(n+1);
    }
    void add(ll i, ll x){
        i+=offs; ll ai = i;
        for (; i<=n; i+=(-i&i)) pref[i]+=x;
        for (i=ai; i; i-=(-i&i)) suff[i]+=x;
    }
    ll get_pref(ll i){
        i+=offs; ll res=0;
        for (; i; i-=(-i&i)) res+=pref[i];
        return res;
    }
    ll get_suff(ll i){
        i+=offs; ll res=0;
        for (; i<=n; i+=(-i&i)) res+=suff[i];
        return res;
    }
};

void solve(){
    ll n, m; cin >> n >> m;
    vector<vector<pair<ll, ll>>> avail(n);
    vector<pair<ll, ll>> d(m);
    for (ll i=0; i<m; i++){
        ll x, p; cin >> x >> p;
        d[i] = {x, p};
        avail[x].push_back({p, i});
    }
    vector<vector<ll>> vis(n, vector<ll>(n+1));
    vector<ll> dist(n, INF); queue<tuple<ll, ll, ll>> que;
    que.push({0, d[0].ff, 0});
    while (!que.empty()){
        auto [w, x, i]=que.front(); que.pop();
        if (vis[x][d[i].ss]) continue;
        vis[x][d[i].ss]=1; dist[i]=min(dist[i], w);
        if (x-d[i].ss>=0 and !vis[x-d[i].ss][d[i].ss]) que.push({w+1, x-d[i].ss, i});
        if (x+d[i].ss<n and !vis[x+d[i].ss][d[i].ss]) que.push({w+1, x+d[i].ss, i});
        for (auto [p, ind]:avail[x]){
            dist[ind]=min(dist[ind], w);
            if (x-d[ind].ss>=0 and !vis[x-d[ind].ss][d[ind].ss]) que.push({w+1, x-d[ind].ss, ind});
            if (x+d[ind].ss<n and !vis[x+d[ind].ss][d[ind].ss]) que.push({w+1, x+d[ind].ss, ind});
        }
    }
    cout << (dist[1]!=INF?dist[1]:-1) << ln;
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    #ifdef LOCAL
    auto start = chrono::high_resolution_clock::now();
    #endif
    #ifndef LOCAL
    freopen("balancing.in", "r", stdin);
    freopen("balancing.out", "w", stdout);
    #endif
    ll testc=1;
    // cin >> testc;
    for (ll __c=1; __c<=testc; __c++) solve();
    #ifdef LOCAL
    auto duration = chrono::duration_cast<chrono::microseconds>(chrono::high_resolution_clock::now() - start);
    cout << setprecision(0) << fixed << "time: " << (double)duration.count()/1000.0 << " milliseconds" << endl;
    #endif
}

Compilation message (stderr)

skyscraper.cpp: In function 'int main()':
skyscraper.cpp:75:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   75 |     freopen("balancing.in", "r", stdin);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~
skyscraper.cpp:76:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   76 |     freopen("balancing.out", "w", stdout);
      |     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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