Submission #702682

#	Time	Username	Problem	Language	Result	Execution time	Memory
702682		jhnah917	Designated Cities (JOI19_designated_cities)	C++14	23 / 100	261 ms	10068 KiB

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];

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) 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]) paths.emplace_back(dfs(i, i, root) + w, i);
    return paths;
}

void Go(int root){
    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);
    }
}

int main(){
    ios_base::sync_with_stdio(false); cin.tie(nullptr);
    cin >> N; assert(N <= 2000);
    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);
    for(int i=1; i<=N; i++) Go(i);
    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 (stderr)

designated_cities.cpp: In function 'void TreeDP(int, int, ll, ll)':
designated_cities.cpp:9:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
    9 |     for(auto [i,w] : G[v]) if(i == b) C1 += w, up += w;
      |              ^
designated_cities.cpp:11:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   11 |     for(auto [i,w] : G[v]) if(i != b) TreeDP(i, v, up, dw+w);
      |              ^
designated_cities.cpp: In lambda function:
designated_cities.cpp:22:18: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   22 |         for(auto [i,w] : G[v]){
      |                  ^
designated_cities.cpp: In function 'std::vector<std::pair<long long int, long long int> > PathsFromRoot(int)':
designated_cities.cpp:30:14: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
   30 |     for(auto [i,w] : G[root]) paths.emplace_back(dfs(i, i, root) + w, i);
      |              ^
designated_cities.cpp: In function 'void Go(int)':
designated_cities.cpp:46:19: 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]
   46 |     for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost2 += paths[i].first);
      |                  ~^~~~~~~~~~~~~
designated_cities.cpp:50:12: 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]
   50 |     if(idx != paths.size()){
      |        ~~~~^~~~~~~~~~~~~~~
designated_cities.cpp:54:23: 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]
   54 |         for(int i=1; i<paths.size(); i++) R[i+2] = max(R[i+2], cost3 += paths[i].first);
      |                      ~^~~~~~~~~~~~~

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