Submission #877888

#	Time	Username	Problem	Language	Result	Execution time	Memory
877888		sysia	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	100 / 100	61 ms	12500 KiB

skyscraper

//Sylwia Sapkowska
#include <bits/stdc++.h>
#pragma GCC optimize("O3", "unroll-loops")
using namespace std;

void __print(int x) {cerr << x;}
void __print(long long x) {cerr << x;}
void __print(long double x) {cerr << x;}
void __print(char x) {cerr << "'" << x << "'";}
void __print(const char *x) {cerr << '"' << x << '"';}
void __print(const string &x) {cerr << '"' << x << '"';}
void __print(bool x) {cerr << (x ? "true" : "false");}

template<typename T, typename V>
void __print(const pair<T, V> &x) {cerr << '{'; __print(x.first); cerr << ", "; __print(x.second); cerr << '}';}
template<typename T>
void __print(const T &x) {int f = 0; cerr << '{'; for (auto &i: x) cerr << (f++ ? ", " : ""), __print(i); cerr << "}";}
void _print() {cerr << "]\n";}
template <typename T, typename... V>
void _print(T t, V... v) {__print(t); if (sizeof...(v)) cerr << ", "; _print(v...);}
#ifdef LOCAL
#define debug(x...) cerr << "[" << #x << "] = ["; _print(x)
#else
#define debug(x...)
#endif

// #define int long long
typedef pair<int, int> T;
const int oo = 1e9+7, K = 30;
const int mod = 998244353;

const int S = 2;

void solve(){
    int n, m; cin >> n >> m;
    vector<vector<T>>g(n*S+2);
    auto ch = [&](int v, int j = 0){return v*S+j;};
    vector<vector<int>>doge(n+1);
    int start, kon;
    for (int i = 0; i<m; i++){
        int v, j; cin >> v >> j;
        if (i == 0) start = ch(v);  
        if (i == 1) kon = ch(v);
        // if (j >= n) continue;
        if (j < S) g[ch(v)].emplace_back(ch(v, j), 0);
        else doge[v].emplace_back(j);
    }
   
    vector<int>dist(n*S+2, oo);
    set<T>s;
    debug(start, kon);
    s.insert({0, start});
    dist[start] = 0;
    while ((int)s.size()){
        auto [d, v] = *s.begin();
        s.erase(s.begin());
        debug(v);
        if (dist[v] < d) continue; 
        //dlugie skoki
        debug(v, doge[v]);
        auto popraw = [&](int what, int from, int c){
            debug(what, from, c);
            if (dist[what] > dist[from] + c){
                dist[what] = dist[from] + c;
                s.insert({dist[what], what});
            }
        };
        if (v%S == 0){
            int vv = v/S;
            for (auto j: doge[vv]){
                for (int u = vv-j, k = 1; u >= 0; u-=j, k++){
                    popraw(ch(u), v, k);
                }
                for (int u = vv+j, k = 1; u<n; u+=j, k++){
                    popraw(ch(u), v, k);
                }
            }
        }
        //jakies inne losowe
        for (auto [x, c]: g[v]){
            popraw(x, v, c);
        }
        //krotkie skoki
        int j = v%S;
        if (j != 0){
            int pos = v-v%S;
            popraw(pos, v, 0);
            int u = pos/S;
            debug(u, j);
            if (u >= j){
                popraw(ch(u-j, j), v, 1);
            }
            if (u + j < n){
                popraw(ch(u+j, j), v, 1);
            }
        }
    }
    int ans = dist[kon];
    if (ans == oo) ans = -1;
    cout << ans << "\n";
}

int32_t main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    cout.tie(0);

    int t = 1;
    //cin >> t;
    while (t--) solve();

    return 0;
}

Compilation message (stderr)

skyscraper.cpp: In function 'void solve()':
skyscraper.cpp:98:23: warning: 'kon' may be used uninitialized in this function [-Wmaybe-uninitialized]
   98 |     int ans = dist[kon];
      |                       ^

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