Submission #717694

#	Submission time	Handle	Problem	Language	Result	Execution time	Memory
717694	2023-04-02T10:53:17 Z	walterw	Designated Cities (JOI19_designated_cities)	C++17	9 / 100	284 ms	44720 KB

designated_cities

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

ll N, Q, Sum, C1, C[202020], R[202020];
vector<pair<ll,ll>> G[202020];
int S[202020], U[202020];

int GetSize(int v, int b=-1){
    S[v] = 1;
    for(auto [i,w] : G[v]) if(i != b && !U[i]) S[v] += GetSize(i, v);
    return S[v];
}

int GetCent(int v, int n, int b=-1){
    for(auto [i,w] : G[v]) if(i != b && !U[i] && S[i]*2 > n) return GetCent(i, n, v);
    return v;
}

void TreeDP(int v, int b=-1, ll up=0, ll dw=0){
    for(auto [i,w] : G[v]) if(i == b) C1 += w, up += w;
    C[v] = dw - up;
    for(auto [i,w] : G[v]) if(i != b) TreeDP(i, v, up, dw+w);
}

ll CostToRoot(int root){
    return C1 + C[root];
}

vector<pair<ll,ll>> PathsFromRoot(int root){
    vector<pair<ll,ll>> paths;
    function<ll(int,int,int)> dfs = [&](int st, int v, int b) -> ll {
        ll mx = 0;
        for(auto [i,w] : G[v]){
            if(i == b || U[i]) continue;
            ll nxt = dfs(st, i, v) + w;
            if(nxt > mx) swap(mx, nxt);
            if(mx != 0) paths.emplace_back(nxt, st);
        }
        return mx;
    };
    for(auto [i,w] : G[root]) if(!U[i]) paths.emplace_back(dfs(i, i, root) + w, i);
    return paths;
}

void Go(int root){
    root = GetCent(root, GetSize(root)); U[root] = 1;

    ll to_root = CostToRoot(root);
    vector<pair<ll,ll>> paths = PathsFromRoot(root);
    sort(paths.begin(), paths.end(), greater<>());

    // case 1. only root
    R[1] = max(R[1], to_root);
    if(paths.empty()) return;

    // case 2. root and some leaves
    ll cost2 = to_root + paths[0].first;
    R[2] = max(R[2], cost2);
    for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost2 += paths[i].first);

    // case 3. only leaves
    int idx = find_if(paths.begin(), paths.end(), [&](auto v){ return paths[0].second != v.second; }) - paths.begin();
    if(idx != paths.size()){
        ll cost3 = to_root + paths[0].first + paths[idx].first;
        paths.erase(paths.begin() + idx);
        R[2] = max(R[2], cost3);
        for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost3 += paths[i].first);
    }

    return;
    for(auto [i,w] : G[root]) if(!U[i]) Go(i);
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    cin >> N;
    for(int i=1; i<N; i++){
        int a, b, c, d; cin >> a >> b >> c >> d; Sum += c + d;
        G[a].emplace_back(b, c); G[b].emplace_back(a, d);
    }
    TreeDP(1);
    Go(1);
    for(int i=2; i<=N; i++) R[i] = max(R[i], R[i-1]);
    cin >> Q;
    for(int i=1,t; i<=Q; i++) cin >> t, cout << Sum - R[t] << "\n";
}

Compilation message

designated_cities.cpp: In function 'void Go(int)':
designated_cities.cpp:60:19: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |     for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost2 += paths[i].first);
      |                  ~^~~~~~~~~~~~~
designated_cities.cpp:64:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   64 |     if(idx != paths.size()){
      |        ~~~~^~~~~~~~~~~~~~~
designated_cities.cpp:68:23: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<long long int, long long int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   68 |         for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost3 += paths[i].first);
      |                      ~^~~~~~~~~~~~~

Subtask #1
0 / 6.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	3 ms	5200 KB	Output isn't correct
2	Halted	0 ms	0 KB	-

Subtask #2
0 / 7.0

#	Verdict	Execution time	Memory	Grader output
1	Incorrect	3 ms	5076 KB	Output isn't correct
2	Halted	0 ms	0 KB	-

Subtask #3
9.0 / 9.0

#	Verdict	Execution time	Memory	Grader output
1	Correct	3 ms	5076 KB	Output is correct
2	Correct	235 ms	28888 KB	Output is correct
3	Correct	284 ms	44720 KB	Output is correct
4	Correct	222 ms	27420 KB	Output is correct
5	Correct	230 ms	28852 KB	Output is correct
6	Correct	266 ms	31600 KB	Output is correct
7	Correct	157 ms	29288 KB	Output is correct
8	Correct	268 ms	39104 KB	Output is correct
9	Correct	157 ms	29164 KB	Output is correct