Submission #528013

#	Time	Username	Problem	Language	Result	Execution time	Memory
528013		Hydrolyzed	Traffic (IOI10_traffic)	C++14	50 / 100	197 ms	262148 KiB

traffic

/*
 * AUTHOR	: Hydrolyzed~
 * SCHOOL	: RYW
 * TASK		: IOI10_traffic
 * ALGO		: Dynamic Programming on Tree
 * DATE		: 19 Feb 2022
 * */

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/rope>

#ifndef _DEBUG
// @==== Libary ====@ //
#include "traffic.h"
// @================@ //
#endif

using namespace std;
using namespace __gnu_pbds;
using namespace __gnu_cxx;

template <typename T> using ordered_set = tree<T, null_type, less<T>, rb_tree_tag, tree_order_statistics_node_update> ;

// @=== Debugger ===@ //
#ifdef _DEBUG
#include "debug.hpp"
#else
#define dbg(...) 0
#endif
// @================@ //

using ll = long long;

const int MxN = 10000100;
int dp[MxN], pp[MxN], res = 1e9 + 1000, res_id;
vector<int> adj[MxN];

void dfs(int u, int p){
	dp[u] = pp[u];
	for(auto x: adj[u]){
		if(x == p){
			continue;
		}
		dfs(x, u);
		dp[u] += dp[x];
	}
}

void dfs2(int u, int p, int last){
	int maxx = last;
	for(auto x: adj[u]){
		if(x == p){
			continue;
		}
		dfs2(x, u, last + dp[u] - dp[x]);
		maxx = max(maxx, dp[x]);
	}
	if(res > maxx){
		res = maxx;
		res_id = u;
	}
}

int LocateCentre(int n, int p[], int s[], int d[]){
	for(int i=0; i<n-1; ++i){
		adj[s[i]].push_back(d[i]);
		adj[d[i]].push_back(s[i]);
	}
	for(int i=0; i<n; ++i){
		pp[i] = p[i];
	}
	dfs(0, 0);
	dfs2(0, 0, 0);
	return res_id;
}

#ifdef _DEBUG
static int N,P[1000000],S[1000000],D[1000000];

int main(){
   int i;
   scanf("%d",&N);
   for (i=0;i<N;i++) scanf("%d",&P[i]);
   for (i=0;i<N-1;i++) scanf("%d%d",&S[i],&D[i]);
   int r = LocateCentre(N,P,S,D);
   printf("%d\n",r);
   return 0;
}
#endif
/*
inline void solution(){
	
	return ;
}

signed main(){
	cin.tie(nullptr)->ios::sync_with_stdio(false);	
	int q = 1;
//	cin >> q;
	while(q--){
		solution();
		cout << "\n";
	}
	return 0;
}
*/
// https://github.com/MasterIceZ/archive/tree/main/cpp-template

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