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Submission #256799

# Submission time Handle Problem Language Result Execution time Memory
256799 2020-08-03T08:27:04 Z Nightlight Beads and wires (APIO14_beads) C++14
100 / 100
 252 ms 27628 KB 
#include <bits/stdc++.h>
#define pii pair<int, int>
#define INF 1000000000000000000
using namespace std;

int N;
long long dp0[200005];//side 
long long dp1[200005];//mid connect to 2 chlid (2 side or 1 side and 1 mid)
long long dp2[200005];//mid connect to 1 parent and 1 child (parent is side and child is mid) 
long long dp3[200005];//mid connect to 1 parent and 1 child (parent can be side or mid, child is side)

vector<pii> adj[200005];

void DFS(int u, int p) {
  int v, w;
  long long bs = -INF, bs2 = -INF, bm = -INF, bm2 = -INF;
  int id_bs = 0, id_bs2 = 0, id_bm = 0, id_bm2 = 0;
  long long cur_side, cur_mid, best = 0, sum = 0, best_md = 0;
  for(pii now : adj[u]) {
    v = now.first, w = now.second;
    if(v == p) continue;
    DFS(v, u);
    dp2[v] += w, dp3[v] += w;

    best = max(dp0[v], dp2[v]);
    sum += best;
    best_md = max(best_md, max(dp1[v], dp3[v]) - best);

    //best if choosen
    cur_side = dp0[v] + w - best;
    if(cur_side > bs) {
      bs2 = bs, id_bs2 = id_bs;
      bs = cur_side;
      id_bs = v;
    }else if(cur_side > bs2) {
      bs2 = cur_side;
      id_bs2 = v;
    }

    cur_mid = dp1[v] + w - best;
    if(cur_mid > bm) {
      bm2 = bm, id_bm2 = id_bm;
      bm = cur_mid;
      id_bm = v;
    }else if(cur_mid > bm2) {
      bm2 = cur_mid;
      id_bm2 = v;
    }
  }
  dp0[u] = sum;
  //if mid connect 2 child
  //1 side 1 mid
  if(id_bs != id_bm) {
    dp1[u] = sum + bs + bm;
  }else {
    dp1[u] = sum + max(bs + bm2, bs2 + bm);
  }
  dp1[u] = max(dp1[u], sum + bs + bs2);
  dp1[u] = max(dp1[u], sum + best_md);

  //if mid connect a parent and 1 red child
  dp2[u] = sum + bs;
  //if mid connect a red parent and a child
  dp3[u] = sum + bm;
//  cout << u << " " << dp0[u] << "\n";
}

int main() {
//  freopen("inp.in", "r", stdin);
//  freopen("out.out", "w", stdout);
  scanf("%d", &N);
  int u, v, w;
//  cout << N << "\n";
  for(int i = 1; i < N; i++) {
    scanf("%d %d %d", &u, &v, &w);
    adj[u].emplace_back(v, w);
    adj[v].emplace_back(u, w);
  }
  DFS(1, 0);
  cout << max(dp0[1], dp1[1]) << "\n";
  cin >> N;
}
/*
10
4 10 2
1 2 21
1 3 13
6 7 1
7 9 5
2 4 3
2 5 8
1 6 55
6 8 34
*/

Compilation message

beads.cpp: In function 'void DFS(int, int)':
beads.cpp:17:18: warning: variable 'id_bs2' set but not used [-Wunused-but-set-variable]
   int id_bs = 0, id_bs2 = 0, id_bm = 0, id_bm2 = 0;
                  ^~~~~~
beads.cpp:17:41: warning: variable 'id_bm2' set but not used [-Wunused-but-set-variable]
   int id_bs = 0, id_bs2 = 0, id_bm = 0, id_bm2 = 0;
                                         ^~~~~~
beads.cpp: In function 'int main()':
beads.cpp:71:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d", &N);
   ~~~~~^~~~~~~~~~
beads.cpp:75:10: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
     scanf("%d %d %d", &u, &v, &w);
     ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

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

Subtask #2
15.0 / 15.0

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

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4992 KB Output is correct
2 Correct 3 ms 4992 KB Output is correct
3 Correct 3 ms 4992 KB Output is correct
4 Correct 3 ms 4992 KB Output is correct
5 Correct 3 ms 4992 KB Output is correct
6 Correct 3 ms 4992 KB Output is correct
7 Correct 3 ms 4992 KB Output is correct
8 Correct 3 ms 4992 KB Output is correct
9 Correct 3 ms 4992 KB Output is correct
10 Correct 4 ms 4992 KB Output is correct
11 Correct 3 ms 4992 KB Output is correct
12 Correct 3 ms 4992 KB Output is correct
13 Correct 3 ms 4992 KB Output is correct
14 Correct 3 ms 5120 KB Output is correct
15 Correct 4 ms 4992 KB Output is correct
16 Correct 4 ms 4992 KB Output is correct
17 Correct 3 ms 4992 KB Output is correct
18 Correct 6 ms 4992 KB Output is correct
19 Correct 3 ms 4992 KB Output is correct
20 Correct 3 ms 4992 KB Output is correct
21 Correct 3 ms 4992 KB Output is correct
22 Correct 3 ms 4992 KB Output is correct
23 Correct 6 ms 5504 KB Output is correct
24 Correct 6 ms 5504 KB Output is correct
25 Correct 6 ms 5504 KB Output is correct
26 Correct 9 ms 5888 KB Output is correct
27 Correct 10 ms 5888 KB Output is correct
28 Correct 8 ms 5888 KB Output is correct
29 Correct 8 ms 5888 KB Output is correct
30 Correct 8 ms 5888 KB Output is correct
31 Correct 9 ms 6400 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 3 ms 4992 KB Output is correct
2 Correct 3 ms 4992 KB Output is correct
3 Correct 3 ms 4992 KB Output is correct
4 Correct 3 ms 4992 KB Output is correct
5 Correct 3 ms 4992 KB Output is correct
6 Correct 3 ms 4992 KB Output is correct
7 Correct 3 ms 4992 KB Output is correct
8 Correct 3 ms 4992 KB Output is correct
9 Correct 3 ms 4992 KB Output is correct
10 Correct 4 ms 4992 KB Output is correct
11 Correct 3 ms 4992 KB Output is correct
12 Correct 3 ms 4992 KB Output is correct
13 Correct 3 ms 4992 KB Output is correct
14 Correct 3 ms 5120 KB Output is correct
15 Correct 4 ms 4992 KB Output is correct
16 Correct 4 ms 4992 KB Output is correct
17 Correct 3 ms 4992 KB Output is correct
18 Correct 6 ms 4992 KB Output is correct
19 Correct 3 ms 4992 KB Output is correct
20 Correct 3 ms 4992 KB Output is correct
21 Correct 3 ms 4992 KB Output is correct
22 Correct 3 ms 4992 KB Output is correct
23 Correct 6 ms 5504 KB Output is correct
24 Correct 6 ms 5504 KB Output is correct
25 Correct 6 ms 5504 KB Output is correct
26 Correct 9 ms 5888 KB Output is correct
27 Correct 10 ms 5888 KB Output is correct
28 Correct 8 ms 5888 KB Output is correct
29 Correct 8 ms 5888 KB Output is correct
30 Correct 8 ms 5888 KB Output is correct
31 Correct 9 ms 6400 KB Output is correct
32 Correct 35 ms 9208 KB Output is correct
33 Correct 36 ms 9208 KB Output is correct
34 Correct 35 ms 9208 KB Output is correct
35 Correct 210 ms 22392 KB Output is correct
36 Correct 201 ms 22264 KB Output is correct
37 Correct 252 ms 22264 KB Output is correct
38 Correct 151 ms 22764 KB Output is correct
39 Correct 176 ms 22616 KB Output is correct
40 Correct 212 ms 22624 KB Output is correct
41 Correct 184 ms 27628 KB Output is correct