oj.uz

Submission #284304

# Submission time Handle Problem Language Result Execution time Memory
284304 2020-08-27T08:00:49 Z BeanZ Mousetrap (CEOI17_mousetrap) C++14
45 / 100
 1143 ms 70184 KB 
#include <bits/stdc++.h>

using namespace std;

#define ll int
#define endl '\n'
const int N = 3e6 + 5;
const int mod = 998244353;
ll n, t, m, ban = 0;
vector<ll> node[1000006];
ll dp[1000006], par[1000006], f[1000006];
void dfsFirst(ll u, ll v){
        par[u] = v;
        for (auto j : node[u]){
                if (j == v) continue;
                dfsFirst(j, u);
                f[u] |= f[j];
        }
        if (u == m) f[u] = 1;
}
void dfs(ll u, ll p, ll cnt){
        dp[u] = 0;
        vector<ll> val;
        for (auto j : node[u]){
                if (j == p || j == ban) continue;
                dfs(j, u, 1);
                val.push_back(dp[j] + 1);
        }
        if (val.size()){
                sort(val.begin(), val.end());
                dp[u] += min((ll)val.size(), cnt);
                if (val.size() > cnt) dp[u] += val[val.size() - cnt - 1];
                dp[u] += max(0, (ll)val.size() - cnt - 1);
                //cout << u << " " << dp[u] << endl;
        }
}
int main(){
        ios_base::sync_with_stdio(false);
        cin.tie(0);
        if (fopen("MOUSETRAP.INP", "r")){
                freopen("MOUSETRAP.INP", "r", stdin);
                freopen("MOUSETRAP.OUT", "w", stdout);
        }
        cin >> n >> t >> m;
        for (int i = 1; i < n; i++){
                ll u, v;
                cin >> u >> v;
                node[u].push_back(v);
                node[v].push_back(u);
        }
        dfsFirst(t, t);
        ll ans = 0;
        ll cnt = 0;
        while (true){
                if (m == t) break;
                ll preans = 0;
                dfs(m, par[m], cnt + 1);
                ll cur = par[m];
                preans = dp[m];
                while (cur != t){
                        preans = preans + node[cur].size() - 2;
                        cur = par[cur];
                }
                //cout << preans << " " << dp[m] << endl;
                ans = max(ans, preans - (cnt > 0));
                cnt++;
                ban = m;
                m = par[m];
        }
        cout << ans;
}
/*
13 13 1
1 2
2 3
2 4
1 5
5 6
5 7
1 8
8 9
8 10
1 11
11 12
11 13

10 1 4
1 2
2 3
2 4
3 9
3 5
4 7
4 6
6 8
7 10

14 4 1
1 2
2 5
2 6
5 7
5 8
8 10
6 9
1 3
3 14
3 11
11 12
11 13
1 4

12 12 1
1 2
1 3
3 4
4 5
4 6
3 7
7 8
7 9
3 10
10 11
10 12
*/

Compilation message

mousetrap.cpp: In function 'void dfs(int, int, int)':
mousetrap.cpp:32:32: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   32 |                 if (val.size() > cnt) dp[u] += val[val.size() - cnt - 1];
      |                     ~~~~~~~~~~~^~~~~
mousetrap.cpp: In function 'int main()':
mousetrap.cpp:41:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   41 |                 freopen("MOUSETRAP.INP", "r", stdin);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mousetrap.cpp:42:24: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
   42 |                 freopen("MOUSETRAP.OUT", "w", stdout);
      |                 ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 16 ms 23808 KB Output is correct
3 Correct 16 ms 23808 KB Output is correct
4 Correct 18 ms 23808 KB Output is correct
5 Correct 16 ms 23808 KB Output is correct
6 Correct 17 ms 23824 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 16 ms 23808 KB Output is correct
10 Correct 16 ms 23808 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 402 ms 67200 KB Output is correct
2 Correct 430 ms 62968 KB Output is correct
3 Correct 1141 ms 70184 KB Output is correct
4 Correct 545 ms 49272 KB Output is correct
5 Correct 1143 ms 69496 KB Output is correct
6 Correct 1126 ms 69496 KB Output is correct

Subtask #3
0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 16 ms 23808 KB Output is correct
3 Correct 16 ms 23808 KB Output is correct
4 Correct 18 ms 23808 KB Output is correct
5 Correct 16 ms 23808 KB Output is correct
6 Correct 17 ms 23824 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 16 ms 23808 KB Output is correct
10 Correct 16 ms 23808 KB Output is correct
11 Incorrect 17 ms 23808 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 17 ms 23808 KB Output is correct
2 Correct 16 ms 23808 KB Output is correct
3 Correct 16 ms 23808 KB Output is correct
4 Correct 18 ms 23808 KB Output is correct
5 Correct 16 ms 23808 KB Output is correct
6 Correct 17 ms 23824 KB Output is correct
7 Correct 17 ms 23808 KB Output is correct
8 Correct 16 ms 23808 KB Output is correct
9 Correct 16 ms 23808 KB Output is correct
10 Correct 16 ms 23808 KB Output is correct
11 Correct 402 ms 67200 KB Output is correct
12 Correct 430 ms 62968 KB Output is correct
13 Correct 1141 ms 70184 KB Output is correct
14 Correct 545 ms 49272 KB Output is correct
15 Correct 1143 ms 69496 KB Output is correct
16 Correct 1126 ms 69496 KB Output is correct
17 Incorrect 17 ms 23808 KB Output isn't correct
18 Halted 0 ms 0 KB -