Submission #881128

#	Time	Username	Problem	Language	Result	Execution time	Memory
881128		Lobo	Jakarta Skyscrapers (APIO15_skyscraper)	C++17	57 / 100	1042 ms	92568 KiB

skyscraper

#include<bits/stdc++.h>
using namespace std;
const long long inf = (long long) 1e9 + 10;
const int inf1 = (int) 1e9 + 10;
// #define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()
const int maxn = 3e4+10;

int n, m;
vector<int> dogs[maxn];

void solve() {
    cin >> n >> m;

    int b0,b1;
    for(int i = 0; i < m; i++) {
        int b,p; cin >> b >> p;
        if(i == 0) b0 = b;
        if(i == 1) b1 = b;
        dogs[b].pb(p);
    }

    vector<int> d0(n+1,inf);
    vector<unordered_map<int,int>> d(n+1);

    deque<pair<int,int>> dq;
    d0[b0] = 0;
    dq.push_back(mp(b0,0));
    while(dq.size()) {
        int i = dq.front().fr;
        int p = dq.front().sc;
        dq.pop_front();
        
        if(p == 0) {
            for(auto x : dogs[i]) {
                if(d[i].count(x) == 0 or d[i][x] > d0[i]) {
                    d[i][x] = d0[i];
                    dq.push_front(mp(i,x));
                }
            }
        }
        else {
            if(d0[i] > d[i][p]) {
                d0[i] = d[i][p];
                dq.push_front(mp(i,0));
            }
            int i1;

            i1 = i-p;
            if(i1 >= 0 && i1 <= n-1 && (d[i1].count(p) == 0 or d[i1][p] > d[i][p]+1)) {
                d[i1][p] = d[i][p]+1;
                dq.push_back(mp(i1,p));
            }
            i1 = i+p;
            if(i1 >= 0 && i1 <= n-1 && (d[i1].count(p) == 0 or d[i1][p] > d[i][p]+1)) {
                d[i1][p] = d[i][p]+1;
                dq.push_back(mp(i1,p));
            }
        }
    }

    if(d0[b1] == inf) cout << -1 << endl;
    else cout << d0[b1] << endl;
}
    
int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

Compilation message (stderr)

skyscraper.cpp: In function 'void solve()':
skyscraper.cpp:34:25: warning: 'b0' may be used uninitialized in this function [-Wmaybe-uninitialized]
   34 |     dq.push_back(mp(b0,0));
      |                         ^
skyscraper.cpp:68:13: warning: 'b1' may be used uninitialized in this function [-Wmaybe-uninitialized]
   68 |     if(d0[b1] == inf) cout << -1 << endl;
      |             ^

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