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Submission #26612

# Submission time Handle Problem Language Result Execution time Memory
26612 2017-07-03T12:50:17 Z Bruteforceman Beads and wires (APIO14_beads) C++11
100 / 100
 500 ms 38888 KB 
#include <bits/stdc++.h>
using namespace std;
int n;
vector <int> g[200010];
vector <int> c[200010];
long long dp[200010][2][2];
const long long inf = 1e16;

void dfs(int x, int par, int parCost) {
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int w = c[x][i];
		if(y == par) continue;
		dfs(y, x, w);
	}
	long long sum;
	vector <long long> best;
	
	// solves 10 case when node x is a middle node
	sum = 0;
	long long t1 = -inf;
	long long t2 = -inf; 
	
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][1], dp[y][0][0]);
		sum += add; 
	}
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][1], dp[y][0][0]);
		dp[x][1][0] = max(dp[x][1][0], sum + cost + dp[y][1][0] - add + t2);
		dp[x][1][0] = max(dp[x][1][0], sum + cost + dp[y][0][0] - add + t1);
		t1 = max(t1, cost + dp[y][1][0] - add);
		t2 = max(t2, cost + dp[y][0][0] - add);
	}
	// end case
	
	
	// solves 10 case when node x is not a middle node
	sum = 0;
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][1], dp[y][0][0]);
		sum += add;
		best.push_back(max(dp[y][1][0], dp[y][1][1]) - add);
	}
	sort(best.begin(), best.end());
	reverse(best.begin(), best.end());
	if(best.size() > 0) dp[x][1][0] = max(dp[x][1][0], sum + best[0]);
	best.clear();
	// end case
	
	
	// solves 11 case
	sum = 0;
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][1], dp[y][0][0]);
		sum += add;
		best.push_back(dp[y][1][0] - add + cost);
	}	
	sort(best.begin(), best.end());
	reverse(best.begin(), best.end());
	if(best.size() > 0) {
		dp[x][1][1] = sum + best[0] + parCost;
	} else {
		dp[x][1][1] = -inf;
	}
	best.clear();
	// end case
	
	
	// solves 01 case
	sum = 0;
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][0], dp[y][0][1]);
		sum += add;
		best.push_back(dp[y][0][0] - add + cost);
	}
	sort(best.begin(), best.end());
	reverse(best.begin(), best.end());
	if(best.size() > 0) {
		dp[x][0][1] = sum + best[0] + parCost;
	} else {
		dp[x][0][1] = -inf;
	}
	best.clear();
	// end case
	
	// solves 00 case
	sum = 0;
	for(size_t i = 0; i < g[x].size(); i++) {
		int y = g[x][i];
		int cost = c[x][i];
		if(y == par) continue;
		long long add = max(dp[y][0][0], dp[y][0][1]);
		sum += add;
	}
	dp[x][0][0] = sum;
	// end case
}


int main() {
	scanf("%d", &n);
	for(int i = 1; i < n; i++) {
		int p, q, r;
		scanf("%d %d %d", &p, &q, &r);
		g[p].push_back(q);
		g[q].push_back(p);
		c[p].push_back(r);
		c[q].push_back(r);
	}
	dfs(1, 0, 0);
	long long ans = dp[1][1][0];
	printf("%lld\n", ans);	
	// cout << dp[6][1][0] << endl;
	// cout << dp[3][1][0] << endl;
	// cout << dp[2][0][1] << endl;
	// cout << dp[8][1][0] << endl;
	return 0;
}

Compilation message

beads.cpp: In function 'void dfs(int, int, int)':
beads.cpp:26:7: warning: unused variable 'cost' [-Wunused-variable]
   int cost = c[x][i];
       ^~~~
beads.cpp:48:7: warning: unused variable 'cost' [-Wunused-variable]
   int cost = c[x][i];
       ^~~~
beads.cpp:106:7: warning: unused variable 'cost' [-Wunused-variable]
   int cost = c[x][i];
       ^~~~
beads.cpp: In function 'int main()':
beads.cpp:117:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
beads.cpp:120:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d %d %d", &p, &q, &r);
   ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9728 KB Output is correct
2 Correct 10 ms 9728 KB Output is correct
3 Correct 9 ms 9728 KB Output is correct
4 Correct 10 ms 9728 KB Output is correct
5 Correct 9 ms 9728 KB Output is correct
6 Correct 9 ms 9728 KB Output is correct
7 Correct 9 ms 9728 KB Output is correct
8 Correct 9 ms 9728 KB Output is correct
9 Correct 9 ms 9728 KB Output is correct
10 Correct 9 ms 9728 KB Output is correct
11 Correct 10 ms 9728 KB Output is correct
12 Correct 10 ms 9728 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9728 KB Output is correct
2 Correct 10 ms 9728 KB Output is correct
3 Correct 9 ms 9728 KB Output is correct
4 Correct 10 ms 9728 KB Output is correct
5 Correct 9 ms 9728 KB Output is correct
6 Correct 9 ms 9728 KB Output is correct
7 Correct 9 ms 9728 KB Output is correct
8 Correct 9 ms 9728 KB Output is correct
9 Correct 9 ms 9728 KB Output is correct
10 Correct 9 ms 9728 KB Output is correct
11 Correct 10 ms 9728 KB Output is correct
12 Correct 10 ms 9728 KB Output is correct
13 Correct 10 ms 9728 KB Output is correct
14 Correct 10 ms 9856 KB Output is correct
15 Correct 9 ms 9728 KB Output is correct
16 Correct 10 ms 9728 KB Output is correct
17 Correct 10 ms 9728 KB Output is correct
18 Correct 9 ms 9728 KB Output is correct
19 Correct 9 ms 9728 KB Output is correct
20 Correct 10 ms 9728 KB Output is correct
21 Correct 10 ms 9728 KB Output is correct
22 Correct 10 ms 9728 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9728 KB Output is correct
2 Correct 10 ms 9728 KB Output is correct
3 Correct 9 ms 9728 KB Output is correct
4 Correct 10 ms 9728 KB Output is correct
5 Correct 9 ms 9728 KB Output is correct
6 Correct 9 ms 9728 KB Output is correct
7 Correct 9 ms 9728 KB Output is correct
8 Correct 9 ms 9728 KB Output is correct
9 Correct 9 ms 9728 KB Output is correct
10 Correct 9 ms 9728 KB Output is correct
11 Correct 10 ms 9728 KB Output is correct
12 Correct 10 ms 9728 KB Output is correct
13 Correct 10 ms 9728 KB Output is correct
14 Correct 10 ms 9856 KB Output is correct
15 Correct 9 ms 9728 KB Output is correct
16 Correct 10 ms 9728 KB Output is correct
17 Correct 10 ms 9728 KB Output is correct
18 Correct 9 ms 9728 KB Output is correct
19 Correct 9 ms 9728 KB Output is correct
20 Correct 10 ms 9728 KB Output is correct
21 Correct 10 ms 9728 KB Output is correct
22 Correct 10 ms 9728 KB Output is correct
23 Correct 14 ms 10240 KB Output is correct
24 Correct 13 ms 10240 KB Output is correct
25 Correct 14 ms 10240 KB Output is correct
26 Correct 17 ms 10624 KB Output is correct
27 Correct 20 ms 10744 KB Output is correct
28 Correct 18 ms 10880 KB Output is correct
29 Correct 17 ms 10880 KB Output is correct
30 Correct 18 ms 10880 KB Output is correct
31 Correct 18 ms 11520 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 10 ms 9728 KB Output is correct
2 Correct 10 ms 9728 KB Output is correct
3 Correct 9 ms 9728 KB Output is correct
4 Correct 10 ms 9728 KB Output is correct
5 Correct 9 ms 9728 KB Output is correct
6 Correct 9 ms 9728 KB Output is correct
7 Correct 9 ms 9728 KB Output is correct
8 Correct 9 ms 9728 KB Output is correct
9 Correct 9 ms 9728 KB Output is correct
10 Correct 9 ms 9728 KB Output is correct
11 Correct 10 ms 9728 KB Output is correct
12 Correct 10 ms 9728 KB Output is correct
13 Correct 10 ms 9728 KB Output is correct
14 Correct 10 ms 9856 KB Output is correct
15 Correct 9 ms 9728 KB Output is correct
16 Correct 10 ms 9728 KB Output is correct
17 Correct 10 ms 9728 KB Output is correct
18 Correct 9 ms 9728 KB Output is correct
19 Correct 9 ms 9728 KB Output is correct
20 Correct 10 ms 9728 KB Output is correct
21 Correct 10 ms 9728 KB Output is correct
22 Correct 10 ms 9728 KB Output is correct
23 Correct 14 ms 10240 KB Output is correct
24 Correct 13 ms 10240 KB Output is correct
25 Correct 14 ms 10240 KB Output is correct
26 Correct 17 ms 10624 KB Output is correct
27 Correct 20 ms 10744 KB Output is correct
28 Correct 18 ms 10880 KB Output is correct
29 Correct 17 ms 10880 KB Output is correct
30 Correct 18 ms 10880 KB Output is correct
31 Correct 18 ms 11520 KB Output is correct
32 Correct 78 ms 14516 KB Output is correct
33 Correct 60 ms 14456 KB Output is correct
34 Correct 64 ms 14584 KB Output is correct
35 Correct 383 ms 28920 KB Output is correct
36 Correct 378 ms 28988 KB Output is correct
37 Correct 500 ms 29176 KB Output is correct
38 Correct 315 ms 32268 KB Output is correct
39 Correct 326 ms 31776 KB Output is correct
40 Correct 308 ms 31020 KB Output is correct
41 Correct 423 ms 38888 KB Output is correct