oj.uz

답안 #135279

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
135279 2019-07-24T01:58:00 Z wilwxk 구슬과 끈 (APIO14_beads) C++14
28 / 100
 1000 ms 5880 KB 
#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
 
const int MAXN=2e5+5;
const ll INF=1e18;
vector<pair<int, ll> > g[MAXN];
ll dp[MAXN][2];
int n;
ll respf;
 
void dfs(int cur, int p) {
	dp[cur][0]=0; dp[cur][1]=0;
 
	ll maior=-INF; //maior dp[viz][0]+peso- normal
	for(auto aresta : g[cur]) {
		int viz; ll peso; tie(viz, peso)=aresta;
		if(viz==p) continue;
		dfs(viz, cur);
 
		ll val=max(dp[viz][1]+peso, dp[viz][0]);
		dp[cur][1]+=val;
 
		ll val2=dp[viz][0]+peso;
		val2-=val;
		if(val2>=maior) maior=val2;
	}
 
	if(cur!=p&&g[cur].size()==1) {
		dp[cur][0]=0;
		dp[cur][1]=-INF;
		return;
	}
 
	//os dois estao com soma de max(dp(i, 1)+p, dp(i, 0))
	dp[cur][0]=dp[cur][1];
	dp[cur][1]+=maior;
}
 
int main() {
	scanf("%d", &n);
	for(int i=0; i<n-1; i++) {
		int a, b, c; scanf("%d %d %d", &a, &b, &c);
		g[a].push_back({b, c});
		g[b].push_back({a, c});
	}
 
	int raiz=1; for(int i=1; i<=n; i++) if(g[i].size()!=1) raiz=i;
	dfs(raiz, raiz);
	respf=dp[raiz][0];
 
	for(int i=1; i<=n; i++) dfs(i, i), respf=max(respf, dp[i][0]);
	// for(int i=1; i<=n; i++) printf("%d: %lld %lld\n", i, dp[i][0], dp[i][1]);
 
	if(n<=2) printf("0\n");
	else printf("%lld\n", respf);
}

Compilation message

beads.cpp: In function 'int main()':
beads.cpp:41:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d", &n);
  ~~~~~^~~~~~~~~~
beads.cpp:43:21: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
   int a, b, c; scanf("%d %d %d", &a, &b, &c);
                ~~~~~^~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
13.0 / 13.0

# 결과 실행 시간 메모리 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 7 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 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 4984 KB Output is correct

Subtask #2
15.0 / 15.0

# 결과 실행 시간 메모리 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 7 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 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 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 7 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 7 ms 5112 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 6 ms 4984 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 7 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct

Subtask #3
0 / 29.0

# 결과 실행 시간 메모리 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 7 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 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 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 7 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 7 ms 5112 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 6 ms 4984 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 7 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 978 ms 5496 KB Output is correct
24 Correct 984 ms 5596 KB Output is correct
25 Correct 976 ms 5496 KB Output is correct
26 Execution timed out 1090 ms 5880 KB Time limit exceeded
27 Halted 0 ms 0 KB -

Subtask #4
0 / 43.0

# 결과 실행 시간 메모리 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 7 ms 4984 KB Output is correct
6 Correct 6 ms 4984 KB Output is correct
7 Correct 6 ms 4984 KB Output is correct
8 Correct 6 ms 4984 KB Output is correct
9 Correct 6 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 4984 KB Output is correct
13 Correct 6 ms 4984 KB Output is correct
14 Correct 7 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 7 ms 5112 KB Output is correct
18 Correct 7 ms 5112 KB Output is correct
19 Correct 6 ms 4984 KB Output is correct
20 Correct 6 ms 5112 KB Output is correct
21 Correct 7 ms 5112 KB Output is correct
22 Correct 7 ms 5112 KB Output is correct
23 Correct 978 ms 5496 KB Output is correct
24 Correct 984 ms 5596 KB Output is correct
25 Correct 976 ms 5496 KB Output is correct
26 Execution timed out 1090 ms 5880 KB Time limit exceeded
27 Halted 0 ms 0 KB -