Submission #609608

#	Time	Username	Problem	Language	Result	Execution time	Memory
609608		Soul234	Mag (COCI16_mag)	C++14	120 / 120	448 ms	229040 KiB

mag

#include<bits/stdc++.h>
using namespace std;

void DBG() { cerr << "]\n"; }
template<class H, class... T> void DBG(H h, T... t) {
    cerr << h; if(sizeof...(t)) cerr << ", ";
    DBG(t...);
}
#ifdef LOCAL
#define dbg(...) cerr << "[" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
#else
#define dbg(...) 0
#endif // LOCAL

#define FOR(i,a,b) for(int i = (a) ; i<(b) ; i++)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for(int i = (b)-1 ; i>=(a) ; i--)
#define R0F(i,a) ROF(i,0,a)
#define each(e,a) for(auto &e : (a))
#define sz(v) (int)(v).size()
#define all(v) (v).begin(),(v).end()
#define rall(v) (v).rbegin(),(v).rend()
#define pb push_back
#define tcT template<class T
#define nl "\n"
#define fi first
#define se second

using ll = long long;
using vi = vector<int>;
using pi = pair<int,int>;
using str = string;
tcT> using V = vector<T>;
tcT> using pqg = priority_queue<T,vector<T>,greater<T>>;

void setIO(string NAME = "") {
    cin.tie(0)->sync_with_stdio(0);
    if(sz(NAME)) {
        freopen((NAME + ".inp").c_str(),"r",stdin);
        freopen((NAME + ".out").c_str(),"w",stdout);
    }
}

tcT> bool ckmin(T&a, const T&b) {
    return b < a ? a=b,1 : 0; }
tcT> bool ckmax(T&a, const T&b) {
    return b > a ? a=b,1 : 0; }

const int MOD = 1e9 + 7;

bool less_than(const pi&a, const pi&b) {
    return 1LL*a.fi*b.se < 1LL*a.se*b.fi;
}

const int MX = 1e6+5;
int N, dpmx1[MX], dpmx2[MX], dpup[MX], mag[MX];
vi adj[MX];
pi ans = {MOD, 1};

void dfs1(int u, int p) {
    dpmx1[u] = dpmx2[u] = 0;
    each(v, adj[u]) if(v != p) {
        dfs1(v, u);
        int tmp = mag[v] == 1 ? 1 + dpmx1[v] : 0;
        if(tmp > dpmx1[u]) {
            dpmx2[u] = dpmx1[u];
            dpmx1[u] = tmp;
        }
        else ckmax(dpmx2[u], tmp);
    }
}

void dfs2(int u, int p) {
    if(mag[u] == 1) {
        if(less_than(pi(mag[u], max(dpmx1[u], dpup[u])+1), ans)) ans = pi(mag[u], max(dpmx1[u], dpup[u])+1);
    }
    else {
        vi vals = {dpup[u], dpmx1[u], dpmx2[u]};
        sort(rall(vals));
        if(less_than(pi(mag[u], vals[0] + vals[1]+1), ans)) ans = pi(mag[u], vals[0] + vals[1]+1);
    }
    each(v, adj[u]) if(v != p) {
        if(mag[u] != 1) {
            dpup[v] = 0;
        }
        else {
            int tmp = mag[v] == 1 ? 1 + dpmx1[v] : 0;
            if(tmp == dpmx1[u]) dpup[v] = 1 + max(dpup[u], dpmx2[u]);
            else dpup[v] = 1 + max(dpup[u], dpmx1[u]);
        }
        dfs2(v, u);
    }
}

void solve() {
    cin>>N;
    F0R(i,N-1) {
        int a, b;
        cin>>a>>b;
        adj[a].pb(b);
        adj[b].pb(a);
    }
    FOR(i,1,N+1) cin>>mag[i];
    dfs1(1, -1);
    dfs2(1, -1);
    int gc = __gcd(ans.fi, ans.se);
    ans.fi /= gc, ans.se /= gc;
    cout << ans.fi << "/" << ans.se << nl;
}

int main() {
    setIO();

    int t=1;
    //cin>>t;
    while(t-->0) {
        solve();
    }

    return 0;
}

Compilation message (stderr)

mag.cpp: In function 'void setIO(std::string)':
mag.cpp:39:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   39 |         freopen((NAME + ".inp").c_str(),"r",stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
mag.cpp:40:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   40 |         freopen((NAME + ".out").c_str(),"w",stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 12 / 12
• Subtask 2: 12 / 12
• Subtask 3: 12 / 12
• Subtask 4: 12 / 12
• Subtask 5: 12 / 12
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• Subtask 10: 12 / 12