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Submission #159130

# Submission time Handle Problem Language Result Execution time Memory
159130 2019-10-21T06:28:07 Z sealnot123 Beads and wires (APIO14_beads) C++14
100 / 100
 205 ms 24824 KB 
#include<bits/stdc++.h>
#define x first
#define y second

using namespace std;

typedef pair<int,int> PII;
typedef long long LL;
const int N=200005;

LL dp[N][2], p[N];
vector<PII> g[N];

void DP(int u, int v){
	int ch = 0;
	dp[u][1] = -1e18;
	LL b = -1e18;
	for(PII e: g[u]){
		if(e.x == v) continue;
		DP(e.x, u);
		LL a = max(dp[e.x][0], dp[e.x][1]+e.y);
		dp[u][1] = max(dp[u][1]+a, dp[u][0]+dp[e.x][0]+e.y);
		dp[u][0] += a;	

		p[e.x] = b;
		b = max(b, -a+dp[e.x][0]+e.y);
	}
	b = -1e18;
	for(int i = g[u].size()-1; i >= 0; i--){
		PII e = g[u][i];
		if(e.x == v) continue;
		p[e.x] = max(p[e.x], b);
		LL a = max(dp[e.x][0], dp[e.x][1]+e.y);
		b = max(b, -a+dp[e.x][0]+e.y);
	}
}

LL dfs(int u, int v, LL a, LL b, LL w){
	LL X = max(0ll,max(a,b+w));
	LL ans = dp[u][0]+X;
	//printf("%lld %lld %lld %lld %d\n", ans, a, b, w, u); 
	for(PII e : g[u]){
		if(e.x == v) continue;
		LL c = max(dp[e.x][0], dp[e.x][1]+e.y);
		LL A = dp[u][0]-c+X;
		LL B = dp[u][0]-c+max(p[e.x]+X, a+w);
		ans = max(ans, dfs(e.x, u, A, B, e.y));
	}
	return ans;
}

int main(){
	int i,j,k,l,a,b,c,d;
	int n;
	scanf("%d",&n);
	for(i=1;i<n;i++){
		scanf("%d%d%d",&a,&b,&c);
		g[a].push_back({b,c});
		g[b].push_back({a,c});
	}
	DP(1,1);
	//for(i=1;i<=n;i++) printf("%d %lld %lld %lld\n",i,dp[i][0],dp[i][1],p[i]);
	printf("%lld",dfs(1,1,-1e18,-1e18,0));
	return 0;
}
/*
5 
1 2 10 
1 3 40 
1 4 15 
1 5 20

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 DP(int, int)':
beads.cpp:15:6: warning: unused variable 'ch' [-Wunused-variable]
  int ch = 0;
      ^~
beads.cpp: In function 'int main()':
beads.cpp:53:8: warning: unused variable 'j' [-Wunused-variable]
  int i,j,k,l,a,b,c,d;
        ^
beads.cpp:53:10: warning: unused variable 'k' [-Wunused-variable]
  int i,j,k,l,a,b,c,d;
          ^
beads.cpp:53:12: warning: unused variable 'l' [-Wunused-variable]
  int i,j,k,l,a,b,c,d;
            ^
beads.cpp:53:20: warning: unused variable 'd' [-Wunused-variable]
  int i,j,k,l,a,b,c,d;
                    ^
beads.cpp:55:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
beads.cpp:57:8: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   scanf("%d%d%d",&a,&b,&c);
   ~~~~~^~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4984 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4988 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 7 ms 4984 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5060 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4984 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4988 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 7 ms 4984 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5060 KB Output is correct
13 Correct 6 ms 5216 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 6 ms 4984 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 8 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 4984 KB Output is correct
21 Correct 6 ms 4984 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct

Subtask #3
29.0 / 29.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4984 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4988 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 7 ms 4984 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5060 KB Output is correct
13 Correct 6 ms 5216 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 6 ms 4984 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 8 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 4984 KB Output is correct
21 Correct 6 ms 4984 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 9 ms 5496 KB Output is correct
24 Correct 9 ms 5368 KB Output is correct
25 Correct 9 ms 5368 KB Output is correct
26 Correct 13 ms 5752 KB Output is correct
27 Correct 13 ms 5752 KB Output is correct
28 Correct 12 ms 5880 KB Output is correct
29 Correct 12 ms 5752 KB Output is correct
30 Correct 11 ms 5752 KB Output is correct
31 Correct 13 ms 6136 KB Output is correct

Subtask #4
43.0 / 43.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 4984 KB Output is correct
2 Correct 6 ms 4984 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Correct 6 ms 4984 KB Output is correct
5 Correct 6 ms 4984 KB Output is correct
6 Correct 6 ms 4988 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 7 ms 4984 KB Output is correct
10 Correct 6 ms 4984 KB Output is correct
11 Correct 6 ms 4984 KB Output is correct
12 Correct 6 ms 5060 KB Output is correct
13 Correct 6 ms 5216 KB Output is correct
14 Correct 6 ms 4984 KB Output is correct
15 Correct 6 ms 4984 KB Output is correct
16 Correct 6 ms 4984 KB Output is correct
17 Correct 6 ms 5112 KB Output is correct
18 Correct 8 ms 5112 KB Output is correct
19 Correct 7 ms 5112 KB Output is correct
20 Correct 7 ms 4984 KB Output is correct
21 Correct 6 ms 4984 KB Output is correct
22 Correct 6 ms 5112 KB Output is correct
23 Correct 9 ms 5496 KB Output is correct
24 Correct 9 ms 5368 KB Output is correct
25 Correct 9 ms 5368 KB Output is correct
26 Correct 13 ms 5752 KB Output is correct
27 Correct 13 ms 5752 KB Output is correct
28 Correct 12 ms 5880 KB Output is correct
29 Correct 12 ms 5752 KB Output is correct
30 Correct 11 ms 5752 KB Output is correct
31 Correct 13 ms 6136 KB Output is correct
32 Correct 40 ms 8824 KB Output is correct
33 Correct 41 ms 8824 KB Output is correct
34 Correct 41 ms 8824 KB Output is correct
35 Correct 191 ms 20692 KB Output is correct
36 Correct 175 ms 20716 KB Output is correct
37 Correct 203 ms 20724 KB Output is correct
38 Correct 137 ms 21052 KB Output is correct
39 Correct 141 ms 21264 KB Output is correct
40 Correct 148 ms 20960 KB Output is correct
41 Correct 205 ms 24824 KB Output is correct