Submission #287906

#	Time	Username	Problem	Language	Result	Execution time	Memory
287906		Bill_00	Traffic (IOI10_traffic)	C++14	0 / 100	65 ms	63992 KiB

traffic

#include <traffic.h>
#include <bits/stdc++.h>
#define ll long long 
using namespace std;
vector<long long>adj[1000001];
vector<long long>leaf;
long long p[1000001];
long long sum[1000001];
long long dp[1000001],vis[1000001];
ll b[1000001];
void dfs(ll j){
	if(adj[j].size()==1 && p[j]==adj[j][0]){
		leaf.push_back(j);
		return;
	}
	for(ll i=0;i<adj[j].size();i++){
		if(adj[j][i]!=p[j]){
			p[adj[j][i]]=j;
			dfs(adj[j][i]);
		}
	}
}
long long calc(ll j){
	sum[j]=(long long)b[j];
	for(ll i=0;i<adj[j].size();i++){
		if(adj[j][i]!=p[j]){
			sum[j]+=calc(adj[j][i]);
		}
	}
	return sum[j];
}
void check(ll j){
	for(ll i=0;i<adj[j].size();i++){
		if(vis[adj[j][i]]==0 && adj[j][i]!=p[j]){
			dp[adj[j][i]]=dp[j]-(2*sum[adj[j][i]])+sum[0];
			vis[adj[j][i]]=1;
			check(adj[j][i]);
		}
	}
	if(j!=0){
		dp[p[j]]=dp[j]+2*sum[j]-sum[0];
		check(p[j]);
	}
}
int LocateCentre(int n,int a[],int s[],int d[]){
	for(ll i=0;i<(ll)n;i++){
		b[i]=(ll)a[i];
	}
	memset(vis,0,sizeof(vis));
	for(ll i=0;i<(ll)(n-1);i++){
		adj[(ll)s[i]].push_back((ll)d[i]);
		adj[(ll)d[i]].push_back((ll)s[i]);
	}
	p[0]=-1;
	dfs(0);
	calc(0);
	dp[leaf[0]]=0;
	vis[leaf[0]]=1;
	long long ans=2e9,id;
	check(leaf[0]);
	for(ll i=0;i<(ll)n;i++){
		//cout << dp[i] << endl;
		if(dp[i]<ans){
			id=i;
			ans=dp[i];
		}	
	}
	return id;
}

Compilation message (stderr)

traffic.cpp: In function 'void dfs(long long int)':
traffic.cpp:16:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   16 |  for(ll i=0;i<adj[j].size();i++){
      |             ~^~~~~~~~~~~~~~
traffic.cpp: In function 'long long int calc(long long int)':
traffic.cpp:25:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   25 |  for(ll i=0;i<adj[j].size();i++){
      |             ~^~~~~~~~~~~~~~
traffic.cpp: In function 'void check(long long int)':
traffic.cpp:33:14: warning: comparison of integer expressions of different signedness: 'long long int' and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   33 |  for(ll i=0;i<adj[j].size();i++){
      |             ~^~~~~~~~~~~~~~
traffic.cpp: In function 'int LocateCentre(int, int*, int*, int*)':
traffic.cpp:68:9: warning: 'id' may be used uninitialized in this function [-Wmaybe-uninitialized]
   68 |  return id;
      |         ^~

• Subtask 1: 0 / 25
• Subtask 2: 0 / 25
• Subtask 3: 0 / 25
• Subtask 4: 0 / 25