oj.uz

Submission #157224

# Submission time Handle Problem Language Result Execution time Memory
157224 2019-10-10T07:36:47 Z lyc Mousetrap (CEOI17_mousetrap) C++14
100 / 100
 1086 ms 182320 KB 
#include <bits/stdc++.h>
using namespace std;

typedef long long ll;
typedef long double ld;
typedef pair<int, int> ii;
typedef pair<int, ii> iii;
typedef pair<ii, int> ri3;
#define mp make_pair
#define pb push_back
#define fi first
#define sc second
#define SZ(x) (int)(x).size()
#define ALL(x) begin(x), end(x) 
#define REP(i, n) for (int i = 0; i < n; ++i) 
#define FOR(i, a, b) for (int i = a; i <= b; ++i)
#define RFOR(i, a, b) for (int i = a; i >= b; --i)

const int MX_N = 1e6+5;

int N, T, M, A, B;
vector<int> al[MX_N];
int w[MX_N], d[MX_N], pa[MX_N];
vector<ii> sub[MX_N];

void dfs(int u, int p) {
    for (auto v : al[u]) if (v != p) {
        pa[v] = u;
        d[v] = d[u] + 1;
        w[v] = w[u] + (p==0?0:SZ(al[u])-2);
        dfs(v,u);
    }
    if (SZ(al[u]) != 1) {
        int a = 0, b = 0;
        for (auto v : al[u]) if (v != p) {
            if (w[v] > a) b = a, a = w[v];
            else if (w[v] > b) b = w[v];
        }
        if (b) w[u] = b;
        else w[u] += d[u]+1;
    } else w[u] += d[u];
    //cout << u << " :: " << w[u] << " " << d[u] << "\n";
}

int main() {
    //freopen("in.txt", "r", stdin);
    ios::sync_with_stdio(false);
    cin.tie(0);

    cin >> N >> T >> M;
    FOR(i,1,N-1){
        cin >> A >> B;
        al[A].push_back(B);
        al[B].push_back(A);
    }

    dfs(T,0);
    int lo = -1, hi = 2*N;
    while (hi-lo > 1) {
        int mid = (lo+hi)/2;

        int p, u, i, b, bad = 0;
        for (p = -1, u = M, i = 0, b = 0; pa[u] != 0; p = u, u = pa[u], ++i) {
            //cout << "\tTRAVERSE " << u << endl;
            int x = 0;
            for (int v : al[u]) if (v != pa[u] && v != p) {
                //cout << "\t\tNEI " << v << " :: " << w[v]-(u!=M)-d[u] << endl;
                if (w[v]-(u!=M)-d[u]+b > mid) ++x;
            }
            b += x;
            if (b > i+1) bad = 1;
        }
        if (b > mid) bad = 1;

        //cout << mid << " :: " << bad << endl;
        (bad ? lo : hi) = mid;
    }

    cout << hi << '\n';
}

Subtask #1
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 47352 KB Output is correct
2 Correct 46 ms 47352 KB Output is correct
3 Correct 46 ms 47352 KB Output is correct
4 Correct 46 ms 47352 KB Output is correct
5 Correct 46 ms 47340 KB Output is correct
6 Correct 43 ms 47352 KB Output is correct
7 Correct 45 ms 47356 KB Output is correct
8 Correct 45 ms 47352 KB Output is correct
9 Correct 46 ms 47352 KB Output is correct
10 Correct 46 ms 47352 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 443 ms 90312 KB Output is correct
2 Correct 401 ms 86136 KB Output is correct
3 Correct 919 ms 91548 KB Output is correct
4 Correct 478 ms 75880 KB Output is correct
5 Correct 976 ms 104664 KB Output is correct
6 Correct 945 ms 104828 KB Output is correct

Subtask #3
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 47352 KB Output is correct
2 Correct 46 ms 47352 KB Output is correct
3 Correct 46 ms 47352 KB Output is correct
4 Correct 46 ms 47352 KB Output is correct
5 Correct 46 ms 47340 KB Output is correct
6 Correct 43 ms 47352 KB Output is correct
7 Correct 45 ms 47356 KB Output is correct
8 Correct 45 ms 47352 KB Output is correct
9 Correct 46 ms 47352 KB Output is correct
10 Correct 46 ms 47352 KB Output is correct
11 Correct 46 ms 47372 KB Output is correct
12 Correct 54 ms 47352 KB Output is correct
13 Correct 46 ms 47352 KB Output is correct
14 Correct 52 ms 47460 KB Output is correct
15 Correct 46 ms 47480 KB Output is correct
16 Correct 46 ms 47352 KB Output is correct
17 Correct 46 ms 47352 KB Output is correct
18 Correct 42 ms 47480 KB Output is correct
19 Correct 46 ms 47480 KB Output is correct
20 Correct 46 ms 47428 KB Output is correct
21 Correct 47 ms 47352 KB Output is correct
22 Correct 46 ms 47352 KB Output is correct

Subtask #4
35.0 / 35.0

# Verdict Execution time Memory Grader output
1 Correct 46 ms 47352 KB Output is correct
2 Correct 46 ms 47352 KB Output is correct
3 Correct 46 ms 47352 KB Output is correct
4 Correct 46 ms 47352 KB Output is correct
5 Correct 46 ms 47340 KB Output is correct
6 Correct 43 ms 47352 KB Output is correct
7 Correct 45 ms 47356 KB Output is correct
8 Correct 45 ms 47352 KB Output is correct
9 Correct 46 ms 47352 KB Output is correct
10 Correct 46 ms 47352 KB Output is correct
11 Correct 443 ms 90312 KB Output is correct
12 Correct 401 ms 86136 KB Output is correct
13 Correct 919 ms 91548 KB Output is correct
14 Correct 478 ms 75880 KB Output is correct
15 Correct 976 ms 104664 KB Output is correct
16 Correct 945 ms 104828 KB Output is correct
17 Correct 46 ms 47372 KB Output is correct
18 Correct 54 ms 47352 KB Output is correct
19 Correct 46 ms 47352 KB Output is correct
20 Correct 52 ms 47460 KB Output is correct
21 Correct 46 ms 47480 KB Output is correct
22 Correct 46 ms 47352 KB Output is correct
23 Correct 46 ms 47352 KB Output is correct
24 Correct 42 ms 47480 KB Output is correct
25 Correct 46 ms 47480 KB Output is correct
26 Correct 46 ms 47428 KB Output is correct
27 Correct 47 ms 47352 KB Output is correct
28 Correct 46 ms 47352 KB Output is correct
29 Correct 47 ms 47436 KB Output is correct
30 Correct 443 ms 103680 KB Output is correct
31 Correct 442 ms 103872 KB Output is correct
32 Correct 627 ms 182320 KB Output is correct
33 Correct 532 ms 182136 KB Output is correct
34 Correct 928 ms 104668 KB Output is correct
35 Correct 1086 ms 104776 KB Output is correct
36 Correct 1029 ms 112556 KB Output is correct
37 Correct 1032 ms 112504 KB Output is correct
38 Correct 848 ms 115576 KB Output is correct
39 Correct 808 ms 115388 KB Output is correct
40 Correct 845 ms 115236 KB Output is correct