Submission #137696

#	Time	Username	Problem	Language	Result	Execution time	Memory
137696		abacaba	Mag (COCI16_mag)	C++14	120 / 120	888 ms	260452 KiB

mag

#include <bits/stdc++.h>
using namespace std;
 
#define int long long
 
const int inf = 2e18;
const int N = 2e6 + 15;
int n, m, a[N], dp[N], dpup[N], par[N];
vector <int> g[N];
pair <int, int> ans = make_pair(0LL, 0LL);
bool used[N];

void dfs(int v, int p = 0) {
    int now = 0;
    for(int to : g[v])
        if(p != to) {
            dfs(to, v);
            now = max(now, dp[to]);
        }
    pair <int, int> x = {a[v], dpup[v] + 1LL + now};
    int c = __gcd(x.first, x.second);
    if(c)
        x.first /= c, x.second /= c;
    if(ans == make_pair(0LL, 0LL) || x.first * ans.second < ans.first * x.second)
        ans = x;
}
 
void calc(int v, int p = 0) {
    dp[v] = (a[v] == 1);
    for(int to : g[v])
        if(to != p) {
            calc(to, v);
            if(a[v] == 1)
                dp[v] = max(dp[v], dp[to] + 1);
        }
}

void calc_up(int v, int p = -1, int now = 0) {
    dpup[v] = now;
    multiset <int> cur = {};
    for(int to : g[v])
        if(to != p)
            cur.insert(dp[to]);
    for(int to : g[v]) {
        if(to != p) {
            cur.erase(cur.find(dp[to]));
            calc_up(to, v, (a[v] == 1 ? max((cur.empty() ? 0 : *cur.rbegin()), now) + 1 : 0));
            cur.insert(dp[to]);
        }
    }
}

#undef int
 
int main() {
    #define int long long
    ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
    cin >> n;
    for(int i = 1; i < n; ++i) {
        int u, v;
        cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    for(int i = 1; i <= n; ++i) {
        cin >> a[i];
        pair <int, int> x = {a[i], 1LL};
        if(ans == make_pair(0LL, 0LL) || a[i] < ans.first)
            ans = x;
    }
    calc(1);
    calc_up(1);
    dfs(1);
    cout << ans.first << '/' << ans.second << endl;
    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