Submission #112744

#	Time	Username	Problem	Language	Result	Execution time	Memory
112744		klungs	Election Campaign (JOI15_election_campaign)	C++14	10 / 100	105 ms	24932 KiB

election_campaign

#include<bits/stdc++.h>


#define pii pair<int,int>
#define fi first
#define se second
#define mp make_pair
#define pb push_back
#define eb emplace_back
#define pf push_front
#define pb2 pop_back
#define pf2 pop_front
#define line printf("\n")
#define pq priority_queue
#define rep(k,i,j) for(int k = (int)i;k<(int)j;k++)
#define repd(k,i,j) for(int k = (int)i;k>=(int)j;k--)
#define ll long long
#define ALL(a) a.begin(),a.end()
#define vi vector<int>

using namespace std;

int INF = 1e9+7;

#define vvi vector<vi>

int N, M;
vi A, B, C;
vvi adj;

void bfs(int u, int v, vi &path) {
  vi par(N, -1);
  queue<int> q;
  q.push(u); par[u] = u;
  while (q.size()) {
    int a = q.front(); q.pop();
    for (int b : adj[a]) if (par[b] == -1) {
      q.push(b);
      par[b] = a;
    }
  }
  
  for (int b = v, a = par[v]; b != u; b = par[b], a = par[a]) {
    path.pb(b);    
  }
  path.pb(u);
}

void read(int _N, int _M, vi U, vi V, vi _A, vi _B, vi _C) {
  tie(N, M, A, B, C) = {_N, _M, _A, _B, _C};
  adj.resize(N);
  rep(k, 0, N - 1) {
    U[k]--; V[k]--;
    adj[U[k]].pb(V[k]);
    adj[V[k]].pb(U[k]);
  }
  rep(k, 0, M) {
    A[k]--; B[k]--;
  }
}

vi DP, path, rev;
vvi L, cost;
int dp(int a) {
  if (a < 0) return 0;
  int &ret = DP[a];
  if (ret != -1) return ret;
  
  ret = dp(a - 1);
  rep(k, 0, L[a].size()) {
    int left = L[a][k], val = cost[a][k];
    ret = max(ret, dp(left - 1) + val);
  }
  return ret;
}

int getMaximumVotes(int _N, int _M, vi _U, vi _V, vi _A, vi _B, vi _C) {
  read(_N, _M, _U, _V, _A, _B, _C);
  
  // check degree
  rep(k, 0, N) if (adj[k].size() > 2) 
    return -1;
  
  vi leaf;
  rep(k, 0, N) if (adj[k].size() == 1)
    leaf.pb(k);
  
  bfs(leaf[0], leaf[1], path);
  rev = vi(N);
  rep(k, 0, N) 
    rev[path[k]] = k;
  
  L = cost = vvi(N);
  rep(k, 0, M) {
    A[k] = rev[A[k]], B[k] = rev[B[k]];
    if (A[k] > B[k]) 
      swap(A[k], B[k]);
      
    L[B[k]].pb(A[k]);
    cost[B[k]].pb(C[k]);
  }
  
  // rep(k, 0, N) printf("%")
  DP = vi(N, -1);
  return dp(N - 1);
}

 
// grader.cpp
#include <stdio.h>
#include <vector>
 
int main() {
  int N, M;
  std::vector<int> U, V;
  std::vector<int> A, B, C;
 
  scanf("%d", &N);
  U.resize(N-1); V.resize(N-1);
 
  for (int i = 0 ; i < N-1 ; i++) {
    scanf("%d %d", &U[i], &V[i]);
  }
  scanf("%d", &M);
  A.resize(M); B.resize(M); C.resize(M);
  for (int i = 0 ; i < M ; i++) {
    scanf("%d %d %d", &A[i], &B[i], &C[i]);
  }
 
  int ans = getMaximumVotes(N, M, U, V, A, B, C);
  printf("%d\n", ans);
  
  return 0;
}

Compilation message (stderr)

election_campaign.cpp: In function 'int main()':
election_campaign.cpp:119:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &N);
   ~~~~~^~~~~~~~~~
election_campaign.cpp:123:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d", &U[i], &V[i]);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~
election_campaign.cpp:125:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &M);
   ~~~~~^~~~~~~~~~
election_campaign.cpp:128:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &A[i], &B[i], &C[i]);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 0 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 0 / 30
• Subtask 5: 0 / 10
• Subtask 6: 0 / 40