oj.uz

Submission #597080

# Submission time Handle Problem Language Result Execution time Memory
597080 2022-07-15T13:20:42 Z OttoTheDino Mousetrap (CEOI17_mousetrap) C++17
100 / 100
 645 ms 119704 KB 
#include <bits/stdc++.h>
using namespace std;
 
#define rep(i,s,e)                  for (int i = s; i <= e; ++i)
#define rrep(i,s,e)                 for (int i = s; i >= e; --i)
#define pb                          push_back
#define all(a)                      a.begin(), a.end()
#define len(a)                      (int)a.size()
typedef vector<int> vi;
 
const int mx = 1e6;
vi adj[mx+1], road;
int n, t, m;
 
bool dfs (int u, int p) {
    if (u==t) return 1;
    for (int v : adj[u]) {
        if (v==p) continue;
        if (dfs (v, u)) {
            road.pb(u);
            return 1;
        }
    }
    return 0;
}
 
int dfs2 (int u, int p) {
    if (len(adj[u])<=2) return len(adj[u])-1;
 
    vi nxt;
    for (int v : adj[u]) {
        if (v==p) continue;
        nxt.pb(dfs2 (v, u));
    }
 
    sort(all(nxt),greater<int>());
 
    return nxt[1]+len(adj[u])-1;
}
 
int main() {
    ios::sync_with_stdio(0);
    cin.tie(0);
 
    cin >> n >> t >> m;
 
    rep (i,1,n-1) {
        int u, v; cin >> u >> v;
        adj[u].pb(v);
        adj[v].pb(u);
    }
 
    dfs (m,-1);
 
    int l = len(road), s = 0, lo = 0, hi = mx;
    vi dp[l];
 
    reverse(all(road));
    road.pb(t);
 
    rrep (i,l-1,0) {
        s += max(len(adj[road[i]])-3+(i==0),0);
        for (int v : adj[road[i]]) {
            if ((i>0 && v==road[i-1]) || v==road[i+1]) continue;
            dp[i].pb(dfs2(v,road[i])+s+1);
        }
        sort(all(dp[i]), greater<int>());
        s -= max(len(adj[road[i]])-3+(i==0),0);
        s += max(len(adj[road[i]])-2+(i==0),0);
    }
    
    while (lo<hi) {
        int mid = (lo+hi)/2, x = 0, suc = 1, cnt = 0;
        rep (i,0,l-1) {
            x++;
            int nc = cnt;
            for (int j : dp[i]) {
                if (j+cnt>mid) {
                    x--;
                    nc++;
                }
            }
            suc &= (x>=0);
            cnt = nc;
        }
        if (suc && cnt<=mid) hi = mid;
        else lo = mid+1;
    }
 
    cout << lo << "\n";
 
    return 0;
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 14 ms 23764 KB Output is correct
3 Correct 15 ms 23744 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 13 ms 23680 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23764 KB Output is correct
8 Correct 12 ms 23816 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 313 ms 55352 KB Output is correct
2 Correct 265 ms 51968 KB Output is correct
3 Correct 592 ms 56320 KB Output is correct
4 Correct 262 ms 39992 KB Output is correct
5 Correct 581 ms 56108 KB Output is correct
6 Correct 582 ms 56260 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 14 ms 23764 KB Output is correct
3 Correct 15 ms 23744 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 13 ms 23680 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23764 KB Output is correct
8 Correct 12 ms 23816 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 13 ms 23764 KB Output is correct
12 Correct 13 ms 23820 KB Output is correct
13 Correct 12 ms 23764 KB Output is correct
14 Correct 13 ms 23892 KB Output is correct
15 Correct 12 ms 23812 KB Output is correct
16 Correct 13 ms 23808 KB Output is correct
17 Correct 13 ms 23808 KB Output is correct
18 Correct 12 ms 23804 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 13 ms 23764 KB Output is correct
21 Correct 12 ms 23812 KB Output is correct
22 Correct 14 ms 23732 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 13 ms 23764 KB Output is correct
2 Correct 14 ms 23764 KB Output is correct
3 Correct 15 ms 23744 KB Output is correct
4 Correct 12 ms 23764 KB Output is correct
5 Correct 13 ms 23680 KB Output is correct
6 Correct 12 ms 23764 KB Output is correct
7 Correct 14 ms 23764 KB Output is correct
8 Correct 12 ms 23816 KB Output is correct
9 Correct 12 ms 23764 KB Output is correct
10 Correct 13 ms 23764 KB Output is correct
11 Correct 313 ms 55352 KB Output is correct
12 Correct 265 ms 51968 KB Output is correct
13 Correct 592 ms 56320 KB Output is correct
14 Correct 262 ms 39992 KB Output is correct
15 Correct 581 ms 56108 KB Output is correct
16 Correct 582 ms 56260 KB Output is correct
17 Correct 13 ms 23764 KB Output is correct
18 Correct 13 ms 23820 KB Output is correct
19 Correct 12 ms 23764 KB Output is correct
20 Correct 13 ms 23892 KB Output is correct
21 Correct 12 ms 23812 KB Output is correct
22 Correct 13 ms 23808 KB Output is correct
23 Correct 13 ms 23808 KB Output is correct
24 Correct 12 ms 23804 KB Output is correct
25 Correct 12 ms 23764 KB Output is correct
26 Correct 13 ms 23764 KB Output is correct
27 Correct 12 ms 23812 KB Output is correct
28 Correct 14 ms 23732 KB Output is correct
29 Correct 12 ms 23764 KB Output is correct
30 Correct 305 ms 68360 KB Output is correct
31 Correct 334 ms 68452 KB Output is correct
32 Correct 344 ms 119704 KB Output is correct
33 Correct 245 ms 68560 KB Output is correct
34 Correct 608 ms 69280 KB Output is correct
35 Correct 614 ms 69468 KB Output is correct
36 Correct 645 ms 77300 KB Output is correct
37 Correct 638 ms 77316 KB Output is correct
38 Correct 505 ms 79264 KB Output is correct
39 Correct 563 ms 79220 KB Output is correct
40 Correct 496 ms 79176 KB Output is correct