oj.uz

Submission #445732

# Submission time Handle Problem Language Result Execution time Memory
445732 2021-07-19T12:17:09 Z Nima_Naderi Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1317 ms 249536 KB 
///In the name of GOD
//#pragma GCC optimize("O2")
#include<bits/stdc++.h>
using namespace std;

typedef long long ll;
const ll MXN = 1e6 + 10;
ll n, t, m;
ll dp[MXN], dad[MXN];
ll limb[MXN], deg[MXN];
vector<ll> DpV[MXN], adj[MXN];
bool inp[MXN]; //in path
void prep(ll u){
    inp[u] = (m == u);
    deg[u] = (u == t ? 1 : adj[u].size() - 1);
    for(auto v : adj[u]){
        if(v == dad[u]) continue;
        dad[v] = u, prep(v);
        inp[u] |= inp[v];
    }
}
void dfs(ll u){
    if(dad[u] == t && !inp[u]) return;
    for(auto v : adj[u]){
        if(v == dad[u]) continue;
        limb[v] = limb[u] + deg[u] - (inp[u] && u != m);
        dfs(v);
        if(!inp[v]) DpV[u].push_back(-dp[v]);
    }
    sort(DpV[u].begin(), DpV[u].end());
    if(deg[u] >= 2) dp[u] = -DpV[u][1];
    else dp[u] = limb[u] + (deg[u] > 0);
}
bool check(ll k){
    ll u = m, c = 1; //streak
    while(u != t){
        ll my = lower_bound(DpV[u].begin(), DpV[u].end(), -k) - DpV[u].begin();
        if(c < my || k < my) return 0;
        k -= my, c -= my, u = dad[u], c ++;
    }
    return 1;
}
int main(){
    ios::sync_with_stdio(0);cin.tie(0); cout.tie(0);
    cin >> n >> t >> m;
    if(m == t) return cout << 0, 0;
    for(int i = 1; i < n; i ++){
        ll u, v; cin >> u >> v;
        adj[u].push_back(v), adj[v].push_back(u);
    }
    prep(t), dfs(t);
    ll low = -1, hig = n + 1;
    while(hig - low > 1){
        ll mid = (low + hig) / 2;
        if(check(mid)) hig = mid;
        else           low = mid;
    }
    cout << hig << '\n';
    return 0;
}
/*!
    HE'S AN INSTIGATOR,
    ENEMY ELIMINATOR,
    AND WHEN HE KNOCKS YOU BETTER
    YOU BETTER LET HIM IN.
*/
//! N.N

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 47308 KB Output is correct
2 Correct 27 ms 47212 KB Output is correct
3 Correct 27 ms 47248 KB Output is correct
4 Correct 27 ms 47396 KB Output is correct
5 Correct 28 ms 47332 KB Output is correct
6 Correct 29 ms 47280 KB Output is correct
7 Correct 27 ms 47300 KB Output is correct
8 Correct 27 ms 47212 KB Output is correct
9 Correct 28 ms 47428 KB Output is correct
10 Correct 26 ms 47232 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 486 ms 134424 KB Output is correct
2 Correct 422 ms 125672 KB Output is correct
3 Correct 1278 ms 135720 KB Output is correct
4 Correct 592 ms 91620 KB Output is correct
5 Correct 1223 ms 135724 KB Output is correct
6 Correct 1237 ms 135784 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 47308 KB Output is correct
2 Correct 27 ms 47212 KB Output is correct
3 Correct 27 ms 47248 KB Output is correct
4 Correct 27 ms 47396 KB Output is correct
5 Correct 28 ms 47332 KB Output is correct
6 Correct 29 ms 47280 KB Output is correct
7 Correct 27 ms 47300 KB Output is correct
8 Correct 27 ms 47212 KB Output is correct
9 Correct 28 ms 47428 KB Output is correct
10 Correct 26 ms 47232 KB Output is correct
11 Correct 28 ms 47308 KB Output is correct
12 Correct 28 ms 47324 KB Output is correct
13 Correct 27 ms 47372 KB Output is correct
14 Correct 29 ms 47436 KB Output is correct
15 Correct 29 ms 47376 KB Output is correct
16 Correct 27 ms 47316 KB Output is correct
17 Correct 28 ms 47420 KB Output is correct
18 Correct 28 ms 47308 KB Output is correct
19 Correct 28 ms 47300 KB Output is correct
20 Correct 29 ms 47360 KB Output is correct
21 Correct 28 ms 47328 KB Output is correct
22 Correct 28 ms 47304 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 27 ms 47308 KB Output is correct
2 Correct 27 ms 47212 KB Output is correct
3 Correct 27 ms 47248 KB Output is correct
4 Correct 27 ms 47396 KB Output is correct
5 Correct 28 ms 47332 KB Output is correct
6 Correct 29 ms 47280 KB Output is correct
7 Correct 27 ms 47300 KB Output is correct
8 Correct 27 ms 47212 KB Output is correct
9 Correct 28 ms 47428 KB Output is correct
10 Correct 26 ms 47232 KB Output is correct
11 Correct 486 ms 134424 KB Output is correct
12 Correct 422 ms 125672 KB Output is correct
13 Correct 1278 ms 135720 KB Output is correct
14 Correct 592 ms 91620 KB Output is correct
15 Correct 1223 ms 135724 KB Output is correct
16 Correct 1237 ms 135784 KB Output is correct
17 Correct 28 ms 47308 KB Output is correct
18 Correct 28 ms 47324 KB Output is correct
19 Correct 27 ms 47372 KB Output is correct
20 Correct 29 ms 47436 KB Output is correct
21 Correct 29 ms 47376 KB Output is correct
22 Correct 27 ms 47316 KB Output is correct
23 Correct 28 ms 47420 KB Output is correct
24 Correct 28 ms 47308 KB Output is correct
25 Correct 28 ms 47300 KB Output is correct
26 Correct 29 ms 47360 KB Output is correct
27 Correct 28 ms 47328 KB Output is correct
28 Correct 28 ms 47304 KB Output is correct
29 Correct 27 ms 47308 KB Output is correct
30 Correct 461 ms 147724 KB Output is correct
31 Correct 447 ms 147764 KB Output is correct
32 Correct 517 ms 218288 KB Output is correct
33 Correct 503 ms 249536 KB Output is correct
34 Correct 1292 ms 148920 KB Output is correct
35 Correct 1283 ms 148880 KB Output is correct
36 Correct 1267 ms 157104 KB Output is correct
37 Correct 1317 ms 157088 KB Output is correct
38 Correct 1020 ms 156088 KB Output is correct
39 Correct 1048 ms 156144 KB Output is correct
40 Correct 1102 ms 156120 KB Output is correct