Submission #138174

#	Time	Username	Problem	Language	Result	Execution time	Memory
138174		thebes	Highway Tolls (IOI18_highway)	C++14	100 / 100	471 ms	38856 KiB

highway

#include <bits/stdc++.h>
#include "highway.h"
using namespace std;

typedef long long ll;
const int MN = 150005;
ll m, st, lo, hi, mm, i, x, y, vis[MN], s, t, d[MN], u[MN]; vector<int> q;
map<pair<ll,ll>,ll> id;
vector<ll> adj[MN], tr[MN], ls;
queue<ll> qq;
void sett(ll l){
    for(int i=0;i<q.size();i++)
        q[i]=(i<=l);
}
void dfs(ll n){
    for(auto v : tr[n]){
        ls.push_back(id[{v, n}]);
        d[v] = d[n]+1; dfs(v);
    }
}
void find_pair(int N, vector<int> U, vector<int> V, int A, int B){
    A = B = 0; m = U.size();
    for(i=0;i<m;i++) q.push_back(0);
    for(i=0;i<m;i++){
        x = U[i], y = V[i];
        id[{x,y}]=id[{y,x}]=i;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    st = ask(q);
    lo = 0, hi = m;
    while(lo<hi){
        ll m = lo+hi>>1;
        sett(m);
        bool heh = (ask(q)==st);
        if(heh) lo=m+1;
        else hi=m;
    }
    mm = lo-1; sett(mm);
    x = U[mm+1], y = V[mm+1];
    qq.push(x); qq.push(y); vis[x]=vis[y]=1;
    while(qq.size()){
        x = qq.front(); qq.pop();
        for(auto v : adj[x]){
            if(id[{x,v}]>mm&&!vis[v]){
                vis[v] = 1;
                qq.push(v);
                tr[x].push_back(v);
                u[id[{x,v}]]=1;
            }
        }
    }
    u[mm+1]=1;
    x = U[mm+1], y = V[mm+1];
    dfs(x);
    lo = 0; hi = ls.size();
    while(lo<hi){
        ll mmm = lo+hi>>1;
        for(i=0;i<m;i++) q[i]=!u[i];
        for(i=mmm;i<ls.size();i++) q[ls[i]]=1;
        bool heh = (ask(q)==st);
        if(heh) hi=mmm;
        else lo=mmm+1;
    }
    if(lo==0){
        s = U[mm+1];
    }
    else{
        x = U[ls[lo-1]], y = V[ls[lo-1]];
        if(d[x]>d[y]) s = x;
        else s = y;
    }
    ls.clear();
    x = U[mm+1], y = V[mm+1];
    dfs(y);
    lo = 0; hi = ls.size();
    while(lo<hi){
        ll mmm = lo+hi>>1;
        for(i=0;i<m;i++) q[i]=!u[i];
        for(i=mmm;i<ls.size();i++) q[ls[i]]=1;
        bool heh = (ask(q)==st);
        if(heh) hi=mmm;
        else lo=mmm+1;
    }
    if(lo==0){
        t = V[mm+1];
    }
    else{
        x = U[ls[lo-1]], y = V[ls[lo-1]];
        if(d[x]>d[y]) t = x;
        else t = y;
    }
    answer(s, t);
}

Compilation message (stderr)

highway.cpp: In function 'void sett(ll)':
highway.cpp:12:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   12 |     for(int i=0;i<q.size();i++)
      |                 ~^~~~~~~~~
highway.cpp: In function 'void find_pair(int, std::vector<int>, std::vector<int>, int, int)':
highway.cpp:33:18: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   33 |         ll m = lo+hi>>1;
      |                ~~^~~
highway.cpp:58:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   58 |         ll mmm = lo+hi>>1;
      |                  ~~^~~
highway.cpp:60:20: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   60 |         for(i=mmm;i<ls.size();i++) q[ls[i]]=1;
      |                   ~^~~~~~~~~~
highway.cpp:78:20: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
   78 |         ll mmm = lo+hi>>1;
      |                  ~~^~~
highway.cpp:80:20: warning: comparison of integer expressions of different signedness: 'll' {aka 'long long int'} and 'std::vector<long long int>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   80 |         for(i=mmm;i<ls.size();i++) q[ls[i]]=1;
      |                   ~^~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 7 / 7
• Subtask 3: 6 / 6
• Subtask 4: 33 / 33
• Subtask 5: 18 / 18
• Subtask 6: 31 / 31