Submission #891971

#	Time	Username	Problem	Language	Result	Execution time	Memory
891971		abcvuitunggio	Towns (IOI15_towns)	C++17	49 / 100	15 ms	1116 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
using namespace std;
int n,dist[111][111],u,v,R,sz[111],p[111],cnt;
int d(int u, int v){
    if (u==v)
        return 0;
    if (u>v)
        swap(u,v);
    if (dist[u][v])
        return dist[u][v];
    cnt++;
    return dist[u][v]=getDistance(u,v);
}
int f(int i){
    return (p[i]==i?i:p[i]=f(p[i]));
}
void unite(int i, int j){
    j=f(j);
    i=f(i);
    if (i==j)
        return;
    sz[i]+=sz[j];
    p[j]=i;
}
int calc(int i){
    return d(i,u)-d(i,0)+d(0,u);
}
bool check(int i, int j){
    return (d(u,i)+d(u,j)-d(i,j)>calc(i));
}
int find_majority(vector <int> a){
    if (a.empty())
        return -1;
    if (a.size()==1)
        return a[0];
    vector <int> ve;
    for (int i=0;i+1<a.size();i+=2)
        if (check(a[i],a[i+1])){
            unite(a[i],a[i+1]);
            ve.push_back(a[i]);
        }
        else{
            if (sz[f(a[i])]>sz[f(a[i+1])])
                ve.push_back(a[i]);
            else
                ve.push_back(a[i+1]);
        }
    if (a.size()&1)
        ve.push_back(a.back());
    return find_majority(ve);
}
int check(int i){
    vector <int> ve;
    for (int j=1;j<=n;j++)
        if (calc(j)==i)
            ve.push_back(j);
    iota(p,p+n,0);
    fill(sz,sz+n,1);
    int w=find_majority(ve),cnt=0;
    if (w==-1)
        return 1;
    for (int i:ve)
        if (f(i)!=f(w)&&i==f(i))
            if (check(w,i))
                unite(w,i);
    return 1-(sz[f(w)]>n/2)*2;
}
int hubDistance(int N, int sub){
    cnt=0;
    n=N;
    memset(dist,0,sizeof(dist));
    pair <int, int> mx={0,-1};
    for (int i=0;i<n;i++)
        mx=max(mx,{d(0,i),i});
    u=mx.second;
    mx={0,-1};
    for (int i=0;i<n;i++)
        mx=max(mx,{d(u,i),i});
    v=mx.second,R=1e9,sz[0]=sz[1]=0;
    vector <int> ve;
	for (int i=0;i<n;i++){
        ve.push_back(calc(i));
        R=min(R,abs(d(u,v)-calc(i)));
	}
    sort(ve.begin(),ve.end());
    int ch=-1;
    vector <int> candidates={d(u,v)-R};
    if (R)
        candidates.push_back(d(u,v)+R);
    for (int i:candidates)
        if (i==ve[n/2]||i==ve[(n-1)/2])
            ch=max(ch,check(i));
    return (R+d(u,v))/2*ch;
}

Compilation message (stderr)

towns.cpp: In function 'int d(int, int)':
towns.cpp:5:18: warning: declaration of 'v' shadows a global declaration [-Wshadow]
    5 | int d(int u, int v){
      |              ~~~~^
towns.cpp:4:24: note: shadowed declaration is here
    4 | int n,dist[111][111],u,v,R,sz[111],p[111],cnt;
      |                        ^
towns.cpp:5:11: warning: declaration of 'u' shadows a global declaration [-Wshadow]
    5 | int d(int u, int v){
      |       ~~~~^
towns.cpp:4:22: note: shadowed declaration is here
    4 | int n,dist[111][111],u,v,R,sz[111],p[111],cnt;
      |                      ^
towns.cpp: In function 'int find_majority(std::vector<int>)':
towns.cpp:38:21: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   38 |     for (int i=0;i+1<a.size();i+=2)
      |                  ~~~^~~~~~~~~
towns.cpp: In function 'int check(int)':
towns.cpp:60:29: warning: declaration of 'cnt' shadows a global declaration [-Wshadow]
   60 |     int w=find_majority(ve),cnt=0;
      |                             ^~~
towns.cpp:4:43: note: shadowed declaration is here
    4 | int n,dist[111][111],u,v,R,sz[111],p[111],cnt;
      |                                           ^~~
towns.cpp:63:14: warning: declaration of 'int i' shadows a parameter [-Wshadow]
   63 |     for (int i:ve)
      |              ^
towns.cpp:53:15: note: shadowed declaration is here
   53 | int check(int i){
      |           ~~~~^
towns.cpp:60:29: warning: unused variable 'cnt' [-Wunused-variable]
   60 |     int w=find_majority(ve),cnt=0;
      |                             ^~~
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:69:28: warning: unused parameter 'sub' [-Wunused-parameter]
   69 | int hubDistance(int N, int sub){
      |                        ~~~~^~~

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