Submission #312153

#	Time	Username	Problem	Language	Result	Execution time	Memory
312153		AmineTrabelsi	Traffic (IOI10_traffic)	C++14	75 / 100	5046 ms	43384 KiB

traffic

#include "bits/stdc++.h"
using namespace std;
using ll = long long;
#define pb push_back 
#define mp make_pair
#define f first
#define s second
#define sz(x) ((int)x.size())
#define all(x) x.begin(),x.end()
#define rall(x) x.rbegin(),x.rend()

// Hi
const int M = 1e6;
vector<int> gr[M];
int *people;
ll dfs(int i,int par){
	ll res = people[i];
	for(auto u:gr[i]){
		if(u != par){
			res += dfs(u,i);
		}
	}
	return res;
}
ll GLocateCentre(int n,int p[],int ff[],int d[]){
	// for all but small
	for(int i=0;i<n-1;i++){
		gr[ff[i]].pb(d[i]);
		gr[d[i]].pb(ff[i]);
	}
	people = p;
	ll res = 1e18;
	int city = 0;
	for(int i=0;i<n;i++){
		ll x = 0;
		for(auto u:gr[i]){
			x = max(x,dfs(u,i));
		}
		if(x < res){
			city = i;
			res = x;
		}
	}
	return city;
}
ll SLocateCentre(int n,int p[],int ff[],int d[]){
	// assuming all the cities are in straight line
	// s[i] = i , d[i] = i+1;
	vector<ll> sum(n+1,0);
	for(int i=0;i<n;i++){
		sum[i+1] = sum[i]+p[i];
	}
	ll res = 1e18;
	int city = 0;
	for(int i=1;i<=n;i++){
		ll x = max(sum[i-1],sum[n]-sum[i]);
		if(x <= res){
			city = i;
			res = x;
		}
	}
	return city-1;
	//   1 2 3
	// 0 1 3 6 
}
ll LocateCentre(int n,int p[],int ff[],int d[]){
	// detect subtask type
	for(int i=0;i<n-1;i++){
		if(ff[i] != i || d[i]!=i+1){
			return GLocateCentre(n,p,ff,d);
		}
	}
	return SLocateCentre(n,p,ff,d);
}
/*
int main(){
	int p[5] = {10,10,10,10,50},s[4] = {1,2,3,4},d[4] = {0,0,0,0};
	cout<<LocateCentre(5,p,s,d)<<'\n';
	return 0;
}
*/

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