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Submission #234664

# Submission time Handle Problem Language Result Execution time Memory
234664 2020-05-25T05:03:45 Z AlexLuchianov Beads and wires (APIO14_beads) C++14
57 / 100
 43 ms 6904 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 = 100000;
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 6 ms 2560 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct
3 Correct 6 ms 2816 KB Output is correct
4 Correct 6 ms 2688 KB Output is correct
5 Correct 6 ms 2688 KB Output is correct
6 Correct 6 ms 2688 KB Output is correct
7 Correct 6 ms 2688 KB Output is correct
8 Correct 6 ms 2688 KB Output is correct
9 Correct 6 ms 2688 KB Output is correct
10 Correct 6 ms 2688 KB Output is correct
11 Correct 6 ms 2688 KB Output is correct
12 Correct 6 ms 2688 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2560 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct
3 Correct 6 ms 2816 KB Output is correct
4 Correct 6 ms 2688 KB Output is correct
5 Correct 6 ms 2688 KB Output is correct
6 Correct 6 ms 2688 KB Output is correct
7 Correct 6 ms 2688 KB Output is correct
8 Correct 6 ms 2688 KB Output is correct
9 Correct 6 ms 2688 KB Output is correct
10 Correct 6 ms 2688 KB Output is correct
11 Correct 6 ms 2688 KB Output is correct
12 Correct 6 ms 2688 KB Output is correct
13 Correct 6 ms 2688 KB Output is correct
14 Correct 6 ms 2688 KB Output is correct
15 Correct 6 ms 2688 KB Output is correct
16 Correct 7 ms 2688 KB Output is correct
17 Correct 6 ms 2688 KB Output is correct
18 Correct 6 ms 2688 KB Output is correct
19 Correct 6 ms 2688 KB Output is correct
20 Correct 6 ms 2688 KB Output is correct
21 Correct 6 ms 2688 KB Output is correct
22 Correct 6 ms 2688 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2560 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct
3 Correct 6 ms 2816 KB Output is correct
4 Correct 6 ms 2688 KB Output is correct
5 Correct 6 ms 2688 KB Output is correct
6 Correct 6 ms 2688 KB Output is correct
7 Correct 6 ms 2688 KB Output is correct
8 Correct 6 ms 2688 KB Output is correct
9 Correct 6 ms 2688 KB Output is correct
10 Correct 6 ms 2688 KB Output is correct
11 Correct 6 ms 2688 KB Output is correct
12 Correct 6 ms 2688 KB Output is correct
13 Correct 6 ms 2688 KB Output is correct
14 Correct 6 ms 2688 KB Output is correct
15 Correct 6 ms 2688 KB Output is correct
16 Correct 7 ms 2688 KB Output is correct
17 Correct 6 ms 2688 KB Output is correct
18 Correct 6 ms 2688 KB Output is correct
19 Correct 6 ms 2688 KB Output is correct
20 Correct 6 ms 2688 KB Output is correct
21 Correct 6 ms 2688 KB Output is correct
22 Correct 6 ms 2688 KB Output is correct
23 Correct 9 ms 3072 KB Output is correct
24 Correct 9 ms 3200 KB Output is correct
25 Correct 9 ms 3072 KB Output is correct
26 Correct 12 ms 3584 KB Output is correct
27 Correct 12 ms 3584 KB Output is correct
28 Correct 11 ms 3968 KB Output is correct
29 Correct 11 ms 3712 KB Output is correct
30 Correct 11 ms 3712 KB Output is correct
31 Correct 12 ms 4352 KB Output is correct

Subtask #4
0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 2560 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct
3 Correct 6 ms 2816 KB Output is correct
4 Correct 6 ms 2688 KB Output is correct
5 Correct 6 ms 2688 KB Output is correct
6 Correct 6 ms 2688 KB Output is correct
7 Correct 6 ms 2688 KB Output is correct
8 Correct 6 ms 2688 KB Output is correct
9 Correct 6 ms 2688 KB Output is correct
10 Correct 6 ms 2688 KB Output is correct
11 Correct 6 ms 2688 KB Output is correct
12 Correct 6 ms 2688 KB Output is correct
13 Correct 6 ms 2688 KB Output is correct
14 Correct 6 ms 2688 KB Output is correct
15 Correct 6 ms 2688 KB Output is correct
16 Correct 7 ms 2688 KB Output is correct
17 Correct 6 ms 2688 KB Output is correct
18 Correct 6 ms 2688 KB Output is correct
19 Correct 6 ms 2688 KB Output is correct
20 Correct 6 ms 2688 KB Output is correct
21 Correct 6 ms 2688 KB Output is correct
22 Correct 6 ms 2688 KB Output is correct
23 Correct 9 ms 3072 KB Output is correct
24 Correct 9 ms 3200 KB Output is correct
25 Correct 9 ms 3072 KB Output is correct
26 Correct 12 ms 3584 KB Output is correct
27 Correct 12 ms 3584 KB Output is correct
28 Correct 11 ms 3968 KB Output is correct
29 Correct 11 ms 3712 KB Output is correct
30 Correct 11 ms 3712 KB Output is correct
31 Correct 12 ms 4352 KB Output is correct
32 Correct 43 ms 6904 KB Output is correct
33 Correct 41 ms 6904 KB Output is correct
34 Correct 41 ms 6904 KB Output is correct
35 Runtime error 9 ms 5248 KB Execution killed with signal 11 (could be triggered by violating memory limits)
36 Halted 0 ms 0 KB -