제출 #36901

#	제출 시각	아이디	문제	언어	결과	실행 시간	메모리
36901		mohammad_kilani	구슬과 끈 (APIO14_beads)	C++14	0 / 100	8 ms	6656 KiB

beads

#include <bits/stdc++.h>
using namespace std;
#define mod 1000000007
#define oo 2000000000
const int N = 200010;
vector< pair<int,int> > g[N];
int n , dp[N][2];
pair<int,int> v[N];

int calc(int node,bool b,int prnt,int w){
	if(dp[node][b] != -1) return dp[node][b];
	dp[node][b] = 0 ;
	if(b == 1){
		for(int i=0;i<g[node].size();i++){
			if(g[node][i].first == prnt) continue;
			dp[node][b] += max(calc(g[node][i].first,0,node,g[node][i].second),calc(g[node][i].first,1,node,g[node][i].second));
		}
	}
	else{
		int sum = 0 ;
		for(int i=0;i<g[node].size();i++){
			if(g[node][i].first == prnt){
				v[i] = (make_pair(-1,-1));
				continue;
			}
			int cur = calc(g[node][i].first,0,node,g[node][i].second);
			int cur2 = calc(g[node][i].first,1,node,g[node][i].second);
			v[i] = (make_pair(cur,cur2));
			sum += max(cur,cur2);
		}
		for(int i=0;i<g[node].size();i++){
			if(v[i].first == -1) continue;
			sum -= max(v[i].first,v[i].second);
			sum += w + g[node][i].second + v[i].second;
			dp[node][b] = max(dp[node][b],sum);
			sum -= (w + g[node][i].second + v[i].second);
			sum += max(v[i].first,v[i].second);
		}
	}
	return dp[node][b];
}

int main() {
	//freopen("in.txt","r",stdin);
	scanf("%d",&n);
	for(int i=0;i<n-1;i++){
		int u ,v , w;
		scanf("%d%d%d",&u,&v,&w);
		g[u].push_back(make_pair(v,w));
		g[v].push_back(make_pair(u,w));
	}
	int ans = 0 ;
	for(int i=1;i<=n;i++){
		if(g[i].size() == 1){
			memset(dp,-1,sizeof(dp));
			ans = max(ans,calc(i,1,-1,0));
			memset(dp,-1,sizeof(dp));
			ans = max(ans,calc(g[i][0].first,1,-1,0));
			break;
		}
	}
	cout << ans << endl;
	return 0;
}

컴파일 시 표준 에러 (stderr) 메시지

beads.cpp: In function 'int calc(int, bool, int, int)':
beads.cpp:14:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[node].size();i++){
               ~^~~~~~~~~~~~~~~
beads.cpp:21:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[node].size();i++){
               ~^~~~~~~~~~~~~~~
beads.cpp:31:16: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   for(int i=0;i<g[node].size();i++){
               ~^~~~~~~~~~~~~~~
beads.cpp: In function 'int main()':
beads.cpp:45:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf("%d",&n);
  ~~~~~^~~~~~~~~
beads.cpp:48:8: 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: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43