Submission #591023

#	Time	Username	Problem	Language	Result	Execution time	Memory
591023		Lobo	Designated Cities (JOI19_designated_cities)	C++17	7 / 100	272 ms	41816 KiB

designated_cities

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

const long long inf = (long long) 1e18 + 10;
const int inf1 = (int) 1e9 + 10;
#define int long long
#define dbl long double
#define endl '\n'
#define sc second
#define fr first
#define mp make_pair
#define pb push_back
#define all(x) x.begin(), x.end()

const int maxn = 2e5+10;

int n, q, up[maxn], dw[maxn], h[maxn];
vector<int> g[maxn];
vector<pair<pair<int,int>,pair<int,int>>> edg;

void dfsh(int u, int ant) {
    for(auto id : g[u]) {
        int v = edg[id].fr.fr^edg[id].fr.sc^u;
        if(v == ant) continue;
        if(v == edg[id].fr.fr) {
            swap(edg[id].fr.fr,edg[id].fr.sc);
            swap(edg[id].sc.fr,edg[id].sc.sc);
            //edg[i].sc.fr -> descendo
            //edg[i].sc.sc -> subindo
        }
        h[v] = h[u]+1;
        dfsh(v,u);
    }
}

void dfsdu(int u, int ant) {
    for(auto id : g[u]) {
        int v = edg[id].fr.fr^edg[id].fr.sc^u;
        if(v == ant) continue;
        dw[v] = dw[u]+edg[id].sc.fr;
        up[v] = up[u]+edg[id].sc.sc;
        dfsdu(v,u);
    }
}

void solve() {
    cin >> n;
    int ans = 0;
    for(int i = 0; i < n-1; i++) {
        int u,v,w1,w2;
        cin >> u >> v >> w1 >> w2;
        g[u].pb(i);
        g[v].pb(i);
        ans+= w1+w2;
        edg.pb(mp(mp(u,v),mp(w1,w2)));
    }
    dfsh(1,0);
    int tup = 0;
    for(int i = 0; i < n-1; i++) {
        tup+= edg[i].sc.sc;
    }

    dfsdu(1,0);

    cin >> q;

    int ans1 = 0;
    for(int i = 1; i <= n; i++) {
        ans1 = max(ans1, tup+dw[i]-up[i]);
    }
    cout << ans-ans1 << endl;
}

int32_t main() {
    ios::sync_with_stdio(false); cin.tie(0);

    // freopen("in.in", "r", stdin);
    // freopen("out.out", "w", stdout);
    int tt = 1;
    // cin >> tt;
    while(tt--) {
        solve();
    }

}

• Subtask 1: 0 / 6
• Subtask 2: 7 / 7
• Subtask 3: 0 / 9
• Subtask 4: 0 / 17
• Subtask 5: 0 / 17
• Subtask 6: 0 / 44