Submission #877165

#	Time	Username	Problem	Language	Result	Execution time	Memory
877165		noiaint	Mag (COCI16_mag)	C++17	120 / 120	365 ms	174152 KiB

mag

#include <bits/stdc++.h>
#define int long long

using namespace std;

#ifdef LOCAL
#include "debug.h"
#else
#define debug(...) 42
#endif

#define file ""

#define mp make_pair
#define fi first
#define se second
#define all(x) x.begin(), x.end()

#define bit(x) (1LL << (x))
#define getbit(x, i) (((x) >> (i)) & 1)
#define popcount __builtin_popcountll

mt19937_64 rd(chrono::steady_clock::now().time_since_epoch().count());
int rand(int l, int r) {
    return l + rd() % (r - l + 1);
}

const int N = 1e6 + 5;
const int mod = (int)1e9 + 7; // 998244353;
const int lg = 25; // lg + 1
const int oo = 1e9;
const long long ooo = 1e18;

template<class X, class Y> bool mini(X &a, Y b) {
    return a > b ? (a = b, true) : false;
}
template<class X, class Y> bool maxi(X &a, Y b) {
    return a < b ? (a = b, true) : false;
}
void add(int &a, int b) {
    a += b;
    if (a >= mod) a -= mod;
    if (a < 0) a += mod;
}

int n;
int a[N];
vector<int> adj[N];
int f[N], f2[N];

void update(int u, int c) {
    if (f[u] < c) f2[u] = f[u], f[u] = c;
    else maxi(f2[u], c);
}
void dfsF(int u, int p) {
    for (int v : adj[u]) if (v != p) {
        dfsF(v, u);
        if (a[v] == 1) update(u, f[v] + 1);
    }
}
void dfsG(int u, int p) {
    for (int v : adj[u]) if (v != p) {
        if (a[u] == 1) {
            if (f[u] == f[v] + 1) update(v, f2[u] + 1);
            else update(v, f[u] + 1);
        }
        dfsG(v, u);
    }
}

void process() {
    cin >> n;
    for (int i = 1; i < n; ++i) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    for (int i = 1; i <= n; ++i) cin >> a[i];

    dfsF(1, 0);
    dfsG(1, 0);

    pair<int, int> ans = mp(1e18, 1);
    for (int i = 1; i <= n; ++i) {
        if (a[i] * ans.se < ans.fi * (f[i] + f2[i] + 1)) ans = mp(a[i], f[i] + f2[i] + 1);
    }

    int x = __gcd(ans.fi, ans.se);
    ans.fi /= x;
    ans.se /= x;
    cout << ans.fi << '/' << ans.se;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(0);

    // freopen(file".inp", "r", stdin);
    // freopen(file".out", "w", stdout);

    int tc = 1;
    // cin >> tc;
    
    while (tc--) {
        process();
    }

    return 0;
}

/*

*/

• Subtask 1: 12 / 12
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 12 / 12
• Subtask 5: 12 / 12
• Subtask 6: 12 / 12
• Subtask 7: 12 / 12
• Subtask 8: 12 / 12
• Subtask 9: 12 / 12
• Subtask 10: 12 / 12