Submission #207563

#	Time	Username	Problem	Language	Result	Execution time	Memory
207563		quocnguyen1012	Designated Cities (JOI19_designated_cities)	C++14	100 / 100	428 ms	35064 KiB

designated_cities

#include <bits/stdc++.h>

#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back

using namespace std;
typedef long long ll;

const int maxn = 2e5 + 5;

class Edge
{
public:
  int v, c, d;
  Edge(int v, int c, int d):
    v(v), c(c), d(d) {}
};
vector<Edge> adj[maxn];
int N, M, deg[maxn];
ll res[maxn], sum[maxn];

void prepare(int u, int p = -1)
{
  for(auto v : adj[u]) if(v.v != p){
    prepare(v.v, u);
    sum[u] += v.c + sum[v.v];
  }
}

void down(int u, int p, ll s)
{
  res[1] = min(res[1], s);
  for(auto v : adj[u]) if(v.v != p){
    down(v.v, u, s - v.c + v.d);
  }
}

signed main(void)
{
  ios_base::sync_with_stdio(0); cin.tie(0); cout.tie(0);
  if(fopen("A.INP", "r")){
    freopen("A.INP", "r", stdin);
    freopen("A.OUT", "w", stdout);
  }
  cin >> N;
  for(int i = 1; i < N; ++i){
    int a, b, c, d;
    cin >> a >> b >> c >> d;
    adj[a].eb(b, c, d); adj[b].eb(a, d, c);
    ++deg[a]; ++deg[b];
  }
  res[1] = 1e18;
  prepare(1); down(1, -1, sum[1]);
  priority_queue<pair<ll, int>, vector<pair<ll, int>>, greater<pair<ll, int>>> pq;
  for(int i = 1; i <= N; ++i){
    if(adj[i].size() == 1) pq.push(mp(adj[i][0].d, i));
  }
  while(pq.size() > 2){
    auto now = pq.top(); pq.pop();
    int nxt = -1, cnt = 0;
    for(auto v : adj[now.se]){
      if(deg[v.v] > 1){
        deg[v.v]--;
        if(deg[v.v] == 1) nxt = v.v, ++cnt;
        else res[pq.size()] = res[pq.size() + 1] + now.fi;
      }
    }
    assert(cnt <= 1);
    if(nxt != -1) for(auto v : adj[nxt]) if(deg[v.v] > 1)
        pq.push(mp(now.fi + v.d, nxt));
  }
  int q; cin >> q;
  while(q--){
    int x; cin >> x;
    cout << res[x] << '\n';
  }
}

Compilation message (stderr)

designated_cities.cpp: In function 'int main()':
designated_cities.cpp:45:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("A.INP", "r", stdin);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
designated_cities.cpp:46:12: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
     freopen("A.OUT", "w", stdout);
     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

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