Submission #479947

#	Time	Username	Problem	Language	Result	Execution time	Memory
479947		robell	Traffic (IOI10_traffic)	C++17	50 / 100	495 ms	176300 KiB

traffic

#pragma GCC optimize("O2")
#include <bits/stdc++.h>
#include "traffic.h"
#include <ext/pb_ds/assoc_container.hpp>
using namespace std;
using namespace __gnu_pbds;
typedef tree<int,null_type,less<int>,rb_tree_tag, tree_order_statistics_node_update> indexed_set;
typedef long long ll;
#define pb push_back
#define eb emplace_back
#define countbits __builtin_popcount
#define beg0 __builtin_clz
#define terminal0 __builtin_ctz
int mod=1e9+7;
void setIO(){
    ios::sync_with_stdio(0);
    cin.tie(0); cout.tie(0);
}
void setIO(string f){
	freopen((f+".in").c_str(),"r",stdin);
	freopen((f+".out").c_str(),"w",stdout);
	setIO();
}
int bpop[(int)1e6];//pop in subtree
int bcong[(int)1e6];//max congestion in subtree
int cong[(int)1e6];//tot max congestion
int tot = 0;
int p[(int)1e6];
vector<int> l[(int)1e6];
void findSub(int ind, int parent){
	int maxV = 0;
	int subT = p[ind];
	for (int j:l[ind]){
		if (j!=parent){
			findSub(j,ind);
			maxV=max(maxV,bcong[j]+p[j]);
			subT+=bpop[j];
		}
	}
	bcong[ind]=maxV;
	bpop[ind]=subT;
}
void dfs(int ind, int parent, int above){
	if (ind==0){
		cong[0]=bcong[0];
		for (int j:l[0]){
			dfs(j,ind,bpop[0]-bpop[j]);
		}
	}else{
		cong[ind]=max(bcong[ind],above);
		for (int j:l[ind]){
			if (j!=parent){
				dfs(j,ind,above+bpop[ind]-bpop[j]);
			}
		}
	}
}
int LocateCentre(int N, int P[], int S[], int D[]){
	memset(bpop,0,sizeof(bpop));
	memset(bcong,0,sizeof(bcong));
	memset(cong,-1,sizeof(cong));
	for (int i=0;i<N;i++) p[i]=P[i];
	for (int i=0;i<N-1;i++){
		l[S[i]].pb(D[i]);
		l[D[i]].pb(S[i]);
	}
	findSub(0,0);
	dfs(0,0,0);
	int ind = -1; int minV = 2e9+1;
	for (int i=0;i<N;i++){
		if (cong[i]<minV) minV=cong[i],ind=i;
	}
	return ind;
}

Compilation message (stderr)

traffic.cpp: In function 'void setIO(std::string)':
traffic.cpp:20:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   20 |  freopen((f+".in").c_str(),"r",stdin);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
traffic.cpp:21:9: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   21 |  freopen((f+".out").c_str(),"w",stdout);
      |  ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

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