Submission #772289

#	Time	Username	Problem	Language	Result	Execution time	Memory
772289		Charizard2021	Mag (COCI16_mag)	C++17	0 / 120	805 ms	193432 KiB

mag

#include<bits/stdc++.h>
using namespace std;
#define IOS ios::sync_with_stdio(false);; cin.tie(NULL)
void selfMax(long long& a, long long b){
    a = max(a, b);
}
void selfMin(long long& a, long long b){
    a = min(a, b);
}
template<typename T> istream& operator>>(istream& in, vector<T>& a) {for(auto &x : a) in >> x; return in;};
template<typename T1, typename T2> istream& operator>>(istream& in, pair<T1, T2>& x) {return in >> x.first >> x.second;}

template<typename T1, typename T2> ostream& operator<<(ostream& out, const pair<T1, T2>& x) {return out << x.first << ' ' << x.second;}
template<typename T> ostream& operator<<(ostream& out, vector<T>& a) {for(auto &x : a) out << x << ' '; return out;};
template<typename T> ostream& operator<<(ostream& out, vector<vector<T> >& a) {for(auto &x : a) out << x << '\n'; return out;};
template<typename T1, typename T2> ostream& operator<<(ostream& out, vector<pair<T1, T2> >& a) {for(auto &x : a) out << x << '\n'; return out;};

/*

Use DSU dsu(N);

*/
struct DSU {
	vector<long long> e;
	DSU(long long N) { e = vector<long long>(N, -1); }

	// get representive component (uses path compression)
	long long get(long long x) { return e[x] < 0 ? x : e[x] = get(e[x]); }

	bool same_set(long long a, long long b) { return get(a) == get(b); }

	long long size(long long x) { return -e[get(x)]; }

	bool unite(long long x, long long y) {  // union by size
		x = get(x), y = get(y);
		if (x == y) return false;
		if (e[x] > e[y]) swap(x, y);
		e[x] += e[y]; e[y] = x;
		return true;
	}
};
/*

Run with Bit<long long> BIT

*/
template <class T> class BIT {
    private:
        long long size;
        vector<T> bit;
        vector<T> arr;
    public:
        BIT(long long size) : size(size), bit(size + 1), arr(size) {}
        void set(long long ind, long long val) { add(ind, val - arr[ind]); }
        void add(long long ind, long long val) {
            arr[ind] += val;
            ind++;
            for (; ind <= size; ind += ind & -ind) { bit[ind] += val; }
        }
        T pref_sum(long long ind) {
            ind++;
            T total = 0;
            for (; ind > 0; ind -= ind & -ind) { total += bit[ind]; }
            return total;
        }
};
/*

Change Comb for specific Seg tree probs, but run with Seg<long long> Seg;

*/
template<class T> struct Seg {
	const T ID = 1e18; T comb(T a, T b) { return min(a,b); }
	long long n; vector<T> seg;
	void init(long long _n) { n = _n; seg.assign(2*n,ID); }
	void pull(long long p) { seg[p] = comb(seg[2*p],seg[2*p+1]); }
	void upd(long long p, T val) {
		seg[p += n] = val; for (p /= 2; p; p /= 2) pull(p); }
	T query(long long l, long long r) {
		T ra = ID, rb = ID;
		for (l += n, r += n+1; l < r; l /= 2, r /= 2) {
			if (l&1) ra = comb(ra,seg[l++]);
			if (r&1) rb = comb(seg[--r],rb);
		}
		return comb(ra,rb);
	}
};
const int N = 1000001;
int n;
vector<int> adj[N];
int magic[N];
int dp[2][N];
int up[N];
pair<int, int> ans = make_pair(1e9, 1);
void dfs(int u, int p){
    for(int v : adj[u]){
        if(v != p){
            dfs(v, u);
            if(magic[v] == 1){
                if(dp[0][u] < dp[0][v] + 1){
                    dp[1][u] = dp[0][u];
                    dp[0][u] = dp[0][v] + 1;
                }
                else if(dp[1][u] < dp[0][v] + 1){
                    dp[1][u] = dp[0][v] + 1;
                }
            }
        }
    }
}
void dfs2(int u, int p){
    for(int v : adj[u]){
        if(v != p){
            if(magic[u] == 1){
                up[v] = up[u] + 1;
                if(magic[v] == 1){
                    if(dp[0][v] + 1 == dp[0][u]){
                        up[v] = max(up[v], dp[1][u] + 1);
                    }
                }
                else{
                    up[v] = max(up[v], dp[0][u] + 1);
                }
            }
            dfs2(v, u);
        }
    }
    vector<int> v;
    v.push_back(up[u]);
    v.push_back(dp[0][u]);
    v.push_back(dp[1][u]);
    sort(v.begin(), v.end(), greater<int>());
    if(ans.first * (v[0] + v[1] + 1) < ans.second * magic[u]){
        ans = make_pair(magic[u], (v[0] + v[1] + 1));
    }
}
int main(){
    int n;
    cin >> n;
    for(int i = 0; i < n - 1; i++){
        int a, b;
        cin >> a >> b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    for(int i = 1; i <= n; i++){
        cin >> magic[i];
    }
    dfs(1, 0);
    dfs2(1, 0);
    cout << ans.first/__gcd(ans.first, ans.second) << "/" << ans.second/__gcd(ans.first, ans.second) << "\n";
}

• Subtask 1: 0 / 12
• Subtask 2: 0 / 12
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