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Submission #234665

# Submission time Handle Problem Language Result Execution time Memory
234665 2020-05-25T05:04:10 Z AlexLuchianov Beads and wires (APIO14_beads) C++14
100 / 100
 273 ms 31208 KB 
#include <iostream>
#include <vector>
#include <algorithm>
#include <cmath>
#include <cassert>

using namespace std;

using ll = long long;

#define MIN(a, b) (((a) < (b)) ? (a) : (b))
#define MAX(a, b) (((a) < (b)) ? (b) : (a))

int const nmax = 200000;
int const inf = 1000000000;

ll dp[1 + nmax][2];
vector<pair<int,int>> g[1 + nmax];

void dfs(int node, int parent, int up){
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    if(to == parent)
      g[node].erase(g[node].begin() + h);
  }
  ll sum = 0;
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    dfs(to, node, g[node][h].second);
    sum += dp[to][1];
  }
  dp[node][0] = sum;
  dp[node][1] = sum;
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    int cost = g[node][h].second;
    dp[node][1] = max(dp[node][1], sum - dp[to][1] + dp[to][0] + cost + up);
  }
}
ll dp2[1 + nmax][2];

ll maxrange(vector<pair<ll,int>> &temp, int avoid){
  for(int i = 0; i < temp.size(); i++)
    if(temp[i].second != avoid)
      return temp[i].first;
  return 0;
}

void dfs2(int node, int parent, int up){
  dp2[node][1] = max(dp2[node][0], dp2[node][1]);

  ll sum = dp2[node][1];
  vector<pair<ll,int>> temp;
  temp.push_back({-dp2[node][1] + dp2[node][0] + up, parent});
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    sum += dp[to][1];
    temp.push_back({-dp[to][1] + dp[to][0] + g[node][h].second, to});
  }
  sort(temp.begin(), temp.end());
  reverse(temp.begin(), temp.end());

  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    dp2[to][0] = sum - dp[to][1];
    dp2[to][1] = dp2[to][0] + maxrange(temp, to) + g[node][h].second;
  }
  for(int h = 0; h < g[node].size(); h++){
    int to = g[node][h].first;
    int cost = g[node][h].second;
    dfs2(to, node, cost);
  }
}

int main()
{
  ios::sync_with_stdio(0);
  cin.tie(0);

  int n;
  cin >> n;
  for(int i = 1;i < n; i++){
    int x, y, cost;
    cin >> x >> y >> cost;
    g[x].push_back({y, cost});
    g[y].push_back({x, cost});
  }
  dfs(1, 0, 0);
  dp2[1][1] = 0;
  dfs2(1, 0, -inf);
  ll result = 0;
  for(int i = 1;i <= n; i++)
    result = max(result, dp[i][0] + dp2[i][1]);
  cout << result;
  return 0;
}

Compilation message

beads.cpp: In function 'void dfs(int, int, int)':
beads.cpp:21:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~
beads.cpp:27:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~
beads.cpp:34:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~
beads.cpp: In function 'll maxrange(std::vector<std::pair<long long int, int> >&, int)':
beads.cpp:43:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i = 0; i < temp.size(); i++)
                  ~~^~~~~~~~~~~~~
beads.cpp: In function 'void dfs2(int, int, int)':
beads.cpp:55:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~
beads.cpp:63:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~
beads.cpp:68:20: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int h = 0; h < g[node].size(); h++){
                  ~~^~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 5120 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 4992 KB Output is correct
6 Correct 7 ms 4992 KB Output is correct
7 Correct 7 ms 4992 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 5120 KB Output is correct
10 Correct 7 ms 5120 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 5120 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 4992 KB Output is correct
6 Correct 7 ms 4992 KB Output is correct
7 Correct 7 ms 4992 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 5120 KB Output is correct
10 Correct 7 ms 5120 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 8 ms 4992 KB Output is correct
14 Correct 9 ms 4992 KB Output is correct
15 Correct 8 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 8 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 13 ms 4992 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 5120 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 4992 KB Output is correct
6 Correct 7 ms 4992 KB Output is correct
7 Correct 7 ms 4992 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 5120 KB Output is correct
10 Correct 7 ms 5120 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 8 ms 4992 KB Output is correct
14 Correct 9 ms 4992 KB Output is correct
15 Correct 8 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 8 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 13 ms 4992 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 10 ms 5376 KB Output is correct
24 Correct 10 ms 5376 KB Output is correct
25 Correct 10 ms 5376 KB Output is correct
26 Correct 14 ms 5760 KB Output is correct
27 Correct 14 ms 5760 KB Output is correct
28 Correct 12 ms 6144 KB Output is correct
29 Correct 13 ms 6144 KB Output is correct
30 Correct 13 ms 5888 KB Output is correct
31 Correct 14 ms 6528 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4992 KB Output is correct
2 Correct 7 ms 4992 KB Output is correct
3 Correct 7 ms 5120 KB Output is correct
4 Correct 7 ms 5120 KB Output is correct
5 Correct 7 ms 4992 KB Output is correct
6 Correct 7 ms 4992 KB Output is correct
7 Correct 7 ms 4992 KB Output is correct
8 Correct 7 ms 5120 KB Output is correct
9 Correct 7 ms 5120 KB Output is correct
10 Correct 7 ms 5120 KB Output is correct
11 Correct 7 ms 4992 KB Output is correct
12 Correct 7 ms 4992 KB Output is correct
13 Correct 8 ms 4992 KB Output is correct
14 Correct 9 ms 4992 KB Output is correct
15 Correct 8 ms 4992 KB Output is correct
16 Correct 7 ms 4992 KB Output is correct
17 Correct 8 ms 4992 KB Output is correct
18 Correct 7 ms 4992 KB Output is correct
19 Correct 7 ms 4992 KB Output is correct
20 Correct 7 ms 5120 KB Output is correct
21 Correct 13 ms 4992 KB Output is correct
22 Correct 7 ms 5120 KB Output is correct
23 Correct 10 ms 5376 KB Output is correct
24 Correct 10 ms 5376 KB Output is correct
25 Correct 10 ms 5376 KB Output is correct
26 Correct 14 ms 5760 KB Output is correct
27 Correct 14 ms 5760 KB Output is correct
28 Correct 12 ms 6144 KB Output is correct
29 Correct 13 ms 6144 KB Output is correct
30 Correct 13 ms 5888 KB Output is correct
31 Correct 14 ms 6528 KB Output is correct
32 Correct 41 ms 8448 KB Output is correct
33 Correct 48 ms 8440 KB Output is correct
34 Correct 43 ms 8448 KB Output is correct
35 Correct 273 ms 22248 KB Output is correct
36 Correct 262 ms 22264 KB Output is correct
37 Correct 262 ms 22264 KB Output is correct
38 Correct 193 ms 25696 KB Output is correct
39 Correct 198 ms 27020 KB Output is correct
40 Correct 203 ms 25944 KB Output is correct
41 Correct 262 ms 31208 KB Output is correct