Submission #891843

#	Time	Username	Problem	Language	Result	Execution time	Memory
891843		abcvuitunggio	Towns (IOI15_towns)	C++17	13 / 100	11 ms	536 KiB

towns

#include "towns.h"
#include <bits/stdc++.h>
using namespace std;
int n,dist[111][111],u,v,R,sz[2],p[111];
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];
    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){
    p[f(j)]=f(i);
}
bool check(int i, int j){
    int x=(d(i,u)+d(i,v)-d(u,v))/2,y=(d(j,u)+d(j,v)-d(u,v))/2;
    return (d(i,j)<x+y);
}
int hubDistance(int N, int sub){
    n=N;
    iota(p,p+n,0);
    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;
	for (int i=0;i<n;i++)
        R=min(R,abs(d(i,u)-d(i,v)));
    vector <int> a,b,tmp;
    for (int i=0;i<n;i++){
        int val=d(i,u)-d(i,v);
        if (val<-R)
            sz[0]++;
        if (val==-R)
            a.push_back(i);
        if (val==R)
            b.push_back(i);
        if (val>R)
            sz[1]++;
    }
    if (!R)
        b.clear();
    R=(R+d(u,v))/2;
    if (max(max(sz[0],sz[1]),(int)min(sz[1]+b.size(),sz[0]+a.size()))>n/2)
        return -R;
    if (min(max(a.size(),sz[1]+b.size()),max(b.size(),sz[0]+a.size()))<=n/2)
        return R;
    if (b.size()+sz[1]>n/2)
        swap(a,b);
    stack <int> st,st2;
    for (int i:a){
        if (st.empty()||!check(st.top(),i)){
            st.push(i);
            if (!st2.empty()){
                st.push(st2.top());
                st2.pop();
            }
        }
        else
            st2.push(i);
    }
    int t=st.top();
    while (!st.empty()){
        int u=st.top();
        if (check(u,t)){
            if (st.size()==1){
                st2.push(st.top());
                st.pop();
            }
            else{
                st.pop();
                st.pop();
            }
        }
        else{
            if (st2.empty())
                return R;
            st.pop();
            st2.pop();
        }
    }
    return (st2.empty()?R:-R);
}

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[2],p[111];
      |                        ^
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[2],p[111];
      |                      ^
towns.cpp: In function 'int hubDistance(int, int)':
towns.cpp:55:71: warning: comparison of integer expressions of different signedness: 'const long unsigned int' and 'int' [-Wsign-compare]
   55 |     if (min(max(a.size(),sz[1]+b.size()),max(b.size(),sz[0]+a.size()))<=n/2)
      |         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^~~~~
towns.cpp:57:23: warning: comparison of integer expressions of different signedness: 'std::vector<int>::size_type' {aka 'long unsigned int'} and 'int' [-Wsign-compare]
   57 |     if (b.size()+sz[1]>n/2)
      |         ~~~~~~~~~~~~~~^~~~
towns.cpp:73:13: warning: declaration of 'u' shadows a global declaration [-Wshadow]
   73 |         int u=st.top();
      |             ^
towns.cpp:4:22: note: shadowed declaration is here
    4 | int n,dist[111][111],u,v,R,sz[2],p[111];
      |                      ^
towns.cpp:24:28: warning: unused parameter 'sub' [-Wunused-parameter]
   24 | int hubDistance(int N, int sub){
      |                        ~~~~^~~

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