Submission #592224

#	Time	Username	Problem	Language	Result	Execution time	Memory
592224		Deepesson	Towns (IOI15_towns)	C++17	35 / 100	18 ms	348 KiB

towns

#include <bits/stdc++.h>
#define MAX 115
int getDistance(int i, int j);
int hubDistance(int N, int sub);
typedef std::pair<int,int> pii;
int dist[MAX][2];
pii MaisDistante(int N,int x,int p){
    int best=-1,alvo=0;
    for(int i=0;i!=N;++i){
        if(i==x)continue;
        int d = getDistance(i,x);
        if(d>best){
            best=d;
            alvo=i;
        }
        dist[i][p]=d;
    }
    return {best,alvo};
}
int dist_centro[MAX];
///Queries usadas: 3N-3
int hubDistance(int N, int sub) {
	pii alpha = MaisDistante(N,0,1);
	pii beta = MaisDistante(N,alpha.second,0);
	MaisDistante(N,beta.second,1);
	int d = beta.first;
	int ans=1e9;
	int eixo;
	int exp_a,exp_b;
	for(int i=0;i!=N;++i){
        if(i==alpha.second||i==beta.second)continue;
        int a = dist[i][0];
        int b = dist[i][1];
        int soma = a+b;
        int subt = soma-d;
        int base = subt/2;
        int custo = std::max(a,b)-base;
        if(custo<ans){///Fora da sub de A ou B
            eixo=i;
            ans=custo;
            exp_a = a-base;
            exp_b = b-base;
        }
	}
	if(sub<=2)
	return ans;
	std::vector<int> fora;
	int grupos[2]={1,1};
    for(int i=0;i!=N;++i){
        if(i==alpha.second||i==beta.second)continue;
        int a = dist[i][0];
        int b = dist[i][1];
        int soma = a+b;
        int subt = soma-d;
        int base = subt/2;
        int custo = std::max(a,b)-base;
        int dist_a = a-base;
        int dist_b = b-base;
        if(dist_a == exp_a && dist_b == exp_b){///Fora da sub de A ou B
            fora.push_back(i);
            dist_centro[i]=base;
        }else {///Na subarvore de A ou B
            if(a>b)grupos[0]++;else grupos[1]++;
        }
	}
	int lim=N/2;
	if(grupos[0]>lim||grupos[1]>lim)return -ans;
	///Para a sub 4
	if(sub==4){
        int sum = N-(grupos[0]+grupos[1]);
        if(sum>lim)return -ans;
        return ans;
	}
	std::vector<pii> opcoes;
	for(auto&x:fora){
        for(int i=0;i!=opcoes.size();++i){
            int p = opcoes[i].first;
            if(getDistance(p,x)==dist_centro[x]+dist_centro[p]){
                ++opcoes[i].second;
                if(opcoes[i].second>lim)return -ans;
                goto safe;
            }
        }
        opcoes.push_back({x,1});
        safe:{}
	}
	return ans;
}

Compilation message (stderr)

towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:56:13: warning: unused variable 'custo' [-Wunused-variable]
   56 |         int custo = std::max(a,b)-base;
      |             ^~~~~
towns.cpp:76:22: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<int, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |         for(int i=0;i!=opcoes.size();++i){
      |                     ~^~~~~~~~~~~~~~~
towns.cpp:28:6: warning: variable 'eixo' set but not used [-Wunused-but-set-variable]
   28 |  int eixo;
      |      ^~~~

• Subtask 1: 13 / 13
• Subtask 2: 12 / 12
• Subtask 3: 0 / 13
• Subtask 4: 10 / 10
• Subtask 5: 0 / 13
• Subtask 6: 0 / 39