Submission #384807

#	Time	Username	Problem	Language	Result	Execution time	Memory
384807		kostia244	Designated Cities (JOI19_designated_cities)	C++17	6 / 100	2092 ms	28268 KiB

designated_cities

#include<bits/stdc++.h>
using namespace std;
using ll = long long;
const int maxn = 2e5 + 12;
int n, cst[2*maxn];
ll edgesum = 0;
vector<array<int, 2>> g[maxn];


ll sub[maxn];
void sub_cost(int v, int p) {
    sub[v] = 0;
    for(auto [i, id] : g[v]) if(i != p) {
        sub_cost(i, v);
        sub[v] += sub[i] + cst[id];
    }
}
ll arb[maxn];
void reroot_cost(int v, int p, ll sum) {
    arb[v] = sum;
    for(auto [i, id] : g[v]) if(i!=p) {
        reroot_cost(i, v, sum-cst[id]+cst[id^1]);
    }
}
ll greedy[maxn], used[maxn];
array<ll, 2> find_leaf(int v, int p) {
    array<ll, 2> ans = {0, v};
    for(auto [i, id] : g[v]) if(i != p) {
        auto t = find_leaf(i, v);
        //cout << t[0]+( cst[id^1]*!used[id^1]) << endl;
        t[0] += cst[id^1]*!used[id^1];
        ans = max(ans, t);
    }
    return ans;
}


int par[maxn], par_edge[maxn];
void find_pars(int v, int p) {
    for(auto [i, id] : g[v]) if(i != p) {
        par[i] = v;
        par_edge[i] = id^1;
        find_pars(i, v);
    }
}

void solve(int v) {
    for(int i = 0; i < 2*n; i++) used[i] = 0;
    find_pars(v, 0);
    sub_cost(v, 0);
    ll cur = sub[v];
    for(int i = 2; i <= n; i++) {
        auto [add, x] = find_leaf(v, 0);
        cur += add;
        greedy[i] = min(greedy[i], edgesum - cur);
        for(; x != v; x = par[x]) {
            used[par_edge[x]] = 1;
        }
    }
}

int main() {
    cin.tie(0)->sync_with_stdio(0);
    cin >> n;
    for(int f, t, x, y, i = 1; i < n; i++) {
        cin >> f >> t >> cst[2*i-1] >> cst[2*i-2];
        edgesum += cst[2*i-1];
        edgesum += cst[2*i-2];
        g[f].push_back({t, 2*i-2});
        g[t].push_back({f, 2*i-1});
    }
    sub_cost(1, 0);
    reroot_cost(1, 0, sub[1]);
    memset(greedy, 0x4f, sizeof greedy);
    for(int i = 1; i <= n; i++) {
        if(g[i].size() == 1) {
            solve(i);
        }
    }
    int q;
    cin >> q;
    greedy[1] = edgesum-*max_element(arb+1, arb+n+1);
    for(int t; q--;) {
        cin >> t;
        cout << greedy[t] << '\n';
    }
}

Compilation message (stderr)

designated_cities.cpp: In function 'int main()':
designated_cities.cpp:65:19: warning: unused variable 'x' [-Wunused-variable]
   65 |     for(int f, t, x, y, i = 1; i < n; i++) {
      |                   ^
designated_cities.cpp:65:22: warning: unused variable 'y' [-Wunused-variable]
   65 |     for(int f, t, x, y, i = 1; i < n; i++) {
      |                      ^

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