oj.uz

답안 #571618

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
571618 2022-06-02T12:20:58 Z piOOE Mousetrap (CEOI17_mousetrap) C++17
45 / 100
 752 ms 80036 KB 
#include <bits/stdc++.h>

using namespace std;

#define sz(x) ((int)size(x))
#define all(x) begin(x), end(x)
#define trace(x) cout << #x << ": " << (x) << endl;

typedef long long ll;

mt19937 rnd(chrono::steady_clock::now().time_since_epoch().count());

int rand(int l, int r) { return (int) ((ll) rnd() % (r - l + 1)) + l; }

template<typename T>
bool ckmn(T &x, T y) {
    if (x > y) {
        x = y;
        return true;
    }
    return false;
}

template<typename T>
bool ckmx(T &x, T y) {
    if (x < y) {
        x = y;
        return true;
    }
    return false;
}

const int N = 1000001, infI = 1e9 + 7;
const ll infL = 3e18;

int n, t, m;
vector<int> g[N];
int dp[N], parent[N], depth[N], deg[N], gg[N], sum_deg[N];
vector<int> tops;

void dfs(int v, int p) {
    parent[v] = p;
    int mx1 = 0, mx2 = 0;
    deg[v] = (p == v ? sz(g[v]) : sz(g[v]) - 1);
    sum_deg[v] = sum_deg[p] + (p == v ? 1 : deg[v]);
    for (int to: g[v]) {
        if (to != p) {
            depth[to] = depth[v] + 1;
            dfs(to, v);
            if (mx1 < dp[to]) {
                mx2 = mx1;
                mx1 = dp[to];
            } else if (mx2 < dp[to]) {
                mx2 = dp[to];
            }
        }
    }
    dp[v] = mx2 + deg[v];
    tops.push_back(v);
}


int main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cin >> n >> t >> m;
    --t, --m;
    if (t == m) {
        exit(1);
    }
    for (int i = 1; i < n; ++i) {
        int a, b;
        cin >> a >> b;
        --a, --b;
        g[a].push_back(b);
        g[b].push_back(a);
    }
    dfs(t, t);
    int l = -1, r = infI;
    while (l + 1 < r) {
        int mid = (l + r) >> 1;
        int x = m, prv = -1;
        int total = sum_deg[m] - depth[m];
        bool ok = total <= mid;
        int can = 0;
        while (ok && x != t) {
            ++can;
            int cnt = 0;
            int nw = 0;
            for (int to: g[x]) {
                if (to != parent[x] && to != prv) {
                    if (dp[to] + total > mid) {
                        ++cnt;
                    } else {
                        ++nw;
                    }
                }
            }
            total -= nw;
            if (cnt > can) {
                ok = false;
            }
            prv = x;
            x = parent[x];
        }
        if (ok) {
            r = mid;
        } else {
            l = mid;
        }
    }
    cout << r;
    return 0;
}

Subtask #1
20.0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 13 ms 23764 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 11 ms 23800 KB Output is correct
5 Correct 14 ms 23832 KB Output is correct
6 Correct 12 ms 23840 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23728 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct

Subtask #2
25.0 / 25.0

# 결과 실행 시간 메모리 Grader output
1 Correct 289 ms 78692 KB Output is correct
2 Correct 272 ms 73216 KB Output is correct
3 Correct 752 ms 79928 KB Output is correct
4 Correct 327 ms 52000 KB Output is correct
5 Correct 672 ms 79984 KB Output is correct
6 Correct 706 ms 80036 KB Output is correct

Subtask #3
0 / 20.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 13 ms 23764 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 11 ms 23800 KB Output is correct
5 Correct 14 ms 23832 KB Output is correct
6 Correct 12 ms 23840 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23728 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Incorrect 12 ms 23764 KB Output isn't correct
12 Halted 0 ms 0 KB -

Subtask #4
0 / 35.0

# 결과 실행 시간 메모리 Grader output
1 Correct 12 ms 23764 KB Output is correct
2 Correct 13 ms 23764 KB Output is correct
3 Correct 12 ms 23764 KB Output is correct
4 Correct 11 ms 23800 KB Output is correct
5 Correct 14 ms 23832 KB Output is correct
6 Correct 12 ms 23840 KB Output is correct
7 Correct 12 ms 23764 KB Output is correct
8 Correct 12 ms 23764 KB Output is correct
9 Correct 12 ms 23728 KB Output is correct
10 Correct 12 ms 23764 KB Output is correct
11 Correct 289 ms 78692 KB Output is correct
12 Correct 272 ms 73216 KB Output is correct
13 Correct 752 ms 79928 KB Output is correct
14 Correct 327 ms 52000 KB Output is correct
15 Correct 672 ms 79984 KB Output is correct
16 Correct 706 ms 80036 KB Output is correct
17 Incorrect 12 ms 23764 KB Output isn't correct
18 Halted 0 ms 0 KB -