Submission #947443

#	Time	Username	Problem	Language	Result	Execution time	Memory
947443		Mestu	Race (IOI11_race)	C++14	100 / 100	689 ms	40240 KiB

race

#include <bits/stdc++.h>
using namespace std;
//#include<ext/pb_ds/assoc_container.hpp>
//#include<ext/pb_ds/tree_policy.hpp>
//using namespace __gnu_pbds;
//typedef tree<int, null_type, less<int>, rb_tree_tag, tree_order_statistics_node_update> pbds; // find_by_order, order_of_key
#define ll long long
#define vi vector<int>
#define pii pair<int, int>
#define pll pair<ll, ll>
#define vvi vector<vi>
#define vll vector<ll>
#define vvll vector<vector<ll>>
#define vpii vector<pair<int,int>>
#define vpll vector<pair<ll,ll>>
int Set(int N, int pos) {return  N = N | (1<<pos);}
int Reset(int N, int pos) {return  N = N & ~(1<<pos);}
bool Cheek(int N, int pos) {return  (bool)(N & (1<<pos));}
#define least_one_pos(x) __builtin_ffs(x)
#define leading_zeros(x) __builtin_clz(x)
#define tailing_zeros(x) __builtin_ctz(x)
#define num_of_one(x) __builtin_popcount(x)
///............x...........///
#define all(a) a.begin(), a.end()
#define allr(a) a.rbegin(), a.rend()
#define mp(a, b) make_pair(a, b)
#define pb push_back
#define UNIQUE(X) (X).erase(unique(all(X)), (X).end())
#define ft cout << "for test"<<endl;
#define print(v) for (auto it : v)cout << it<<" ";cout << endl;
#define cinv(v) for(auto &it : v)cin>>it;
#define PI acos(-1.0)
#define FIO ios_base::sync_with_stdio(0);cin.tie(0);cout.tie(0);
#define t_c int test, cs = 1;cin>>test;while (test--)
///................function.....................///

//#define mod 1000000007
//........constant........///
const ll N = 1e6+5;
void file(){
   freopen("input.txt","r",stdin);
   freopen("output.txt","w",stdout);
}
class CentroidDecomposition{
public:
	vector<vector<pii>>adj;
	vector<bool>removed;
	vector<int>subtree,parent;
	map<int,int>Count;
	int n,root,k;
	ll ans;
	CentroidDecomposition(int _n, int _k){
		n = _n;
		k = _k;
		root=1;
		adj.resize(n+1);
		removed.resize(n+1);
		subtree.resize(n+1);
		parent.resize(n+1);
		ans=INT_MAX;
	}
	void readTree(int H[][2], int L[]){
		for(int i=0; i<n-1; i++){
			int a=H[i][0],b=H[i][1];
			adj[a].push_back({b,L[i]});
			adj[b].push_back({a,L[i]});
		}
		centroid_decomposition(0);
		// cout<<ans<<endl;
	}
	int get_subtree_size(int node, int par=-1){
		subtree[node]=1;
		for(auto x:adj[node])
			if(!removed[x.first] and par!=x.first)
				subtree[node] += get_subtree_size(x.first,node);
		return subtree[node];
	}
 
	int get_centroid(int node, int desired, int par=-1){
		for(auto x:adj[node])
			if(!removed[x.first] and x.first!=par and desired<=subtree[x.first])
				return get_centroid(x.first,desired,node);
		return node;
	}
	void get_cnt(int nd, int par, int d, int l, bool tp){
		if(d>k)return;
		// cout<<nd<<" "<<par<<" "<<d<<" "<<l<<" "<<tp<<endl;
		if(!tp){
			if(Count.find(d)!=Count.end())
				Count[d] = min(Count[d],l);
			else
				Count[d]=l;
			// cout<<"add "<<d<<" "<<Count[d]<<endl;
		}
		else{
			if(Count.find(k-d)!=Count.end()){
				ans = min(ans,(ll)l+Count[k-d]);
				// cout<<k-d<<" update "<<l<<" + "<<Count[k-d]<<endl;
			}
		}
		for(auto x:adj[nd])
			if(!removed[x.first] and x.first!=par)
				get_cnt(x.first,nd,d+x.second,l+1,tp);
	}
	void centroid_decomposition(int node){
		int centroid = get_centroid(node,get_subtree_size(node)>>1);
		removed[centroid]=true;
		// cout<<"centroid "<<centroid<<endl;
		Count.clear();
		Count[0]=0;
		for(auto x:adj[centroid]){
			if(!removed[x.first]){
				get_cnt(x.first,centroid,x.second,1,1);
				get_cnt(x.first,centroid,x.second,1,0);
			}
		}
		for(auto x:adj[centroid]){
			if(!removed[x.first])
				centroid_decomposition(x.first);
		}
	}
};
int best_path(int N, int K, int H[][2], int L[]){
	CentroidDecomposition cd(N,K);
	cd.readTree(H,L);
	cd.centroid_decomposition(1);
	if(cd.ans==INT_MAX)cd.ans=-1;
	return cd.ans;
}

Compilation message (stderr)

race.cpp: In function 'void file()':
race.cpp:41:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   41 |    freopen("input.txt","r",stdin);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~
race.cpp:42:11: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   42 |    freopen("output.txt","w",stdout);
      |    ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

• Subtask 1: 9 / 9
• Subtask 2: 12 / 12
• Subtask 3: 22 / 22
• Subtask 4: 57 / 57