Submission #806658

#	Time	Username	Problem	Language	Result	Execution time	Memory
806658		vjudge1	Let's Win the Election (JOI22_ho_t3)	C++14	10 / 100	1 ms	340 KiB

Main

#include<bits/stdc++.h>
//#pragma GCC optimize("Ofast")
//#pragma GCC target("sse,sse2,sse3,ssse3,sse4,popcnt,abm,mmx,avx,tune=native")
#define fi first
#define se second
#define ll long long
#define ld double
using namespace std ;
const int N = 500 ;
bool flag1 ;
int n, k ;
bool us[N + 1] ;
int a[N + 1], b[N + 1], cnt[(1 << 20)] ;
ld abu = 1e9, dp[(1 << 20)][22] ;
void bfs()
{
    set<pair<ld, pair<int, int>>> s ;
    s.insert({0, {0, 1}}) ;
    while(s.size())
    {
        auto p = *s.begin() ;
        int in = p.se.fi, jn = p.se.se ;
        ld gr = jn ;
        s.erase(s.begin()) ;
        if(p.fi > dp[in][jn])
            continue ;
        for(int j = 0 ; j < n ; j++)
        {
            if(((1 << j) & in))
                continue ;
            if(p.fi + (ld)a[j + 1] / gr < dp[in ^ (1 << j)][jn])
            {
                dp[in ^ (1 << j)][jn] = p.fi + (ld)a[j + 1] / gr ;
                s.insert({p.fi + (ld)a[j + 1] / gr, {in ^ (1 << j), jn}}) ;
            }
            if(b[j + 1] >= a[j + 1] && p.fi + (ld)b[j + 1] / gr < dp[in ^ (1 << j)][jn + 1])
            {
                dp[in ^ (1 << j)][jn + 1] = p.fi + (ld)b[j + 1] / gr ;
                s.insert({p.fi + (ld)b[j + 1] / gr, {in ^ (1 << j), jn + 1}}) ;
            }
        }
    }
}
pair<pair<ld, ld>, int> p[N + 1] ;
void rec(int now, ld sum, ld cnt)
{
    if(now == k)
    {
        abu = min(abu, sum) ;
        return ;
    }
    for(int i = 1 ; i <= n ; i++)
    {
        if(us[i])
            continue ;
        us[i] ^= 1 ;
        rec(now + 1, sum + p[i].fi.fi / cnt, cnt) ;
        if(p[i].fi.se != -1)rec(now + 1, sum + p[i].fi.se / cnt, cnt + 1) ;
        us[i] ^= 1 ;
    }
}
signed main()
{
//    freopen("input.txt", "r", stdin) ;
    ios_base::sync_with_stdio( 0 ) ;
    cin.tie( 0 ) ;
    cout.tie( 0 ) ;
    cin >> n ;
    cin >> k ;
    for(int i = 1 ; i <= n ; i++)
    {
        cin >> a[i] >> b[i] ;
        p[i] = {{a[i], b[i]}, i} ;
        if(p[i].fi.se != -1 && p[i].fi.se != p[i].fi.fi)
            flag1 = 1 ;
    }
    if(!flag1)
    {
        ld ans = 1e9 ;
        vector<pair<pair<ld, ld>, int>> v_pos, v_neg ;
        for(int i = 1 ; i <= n ; i++)
        {
            if(p[i].fi.se == -1)
                v_neg.push_back(p[i]) ;
            else
                v_pos.push_back({{p[i].fi.se, p[i].fi.fi}, i}) ;
        }
        sort(v_pos.begin(), v_pos.end()) ;
        sort(v_neg.begin(), v_neg.end()) ;
        for(int i = -1 ; i < min(k, (int)v_pos.size()) ; i++)
        {
            int now = i + 1, uk1 = i + 1, uk2 = 0 ;
            ld sum = 0, cnt = 1 ;
            for(int j = 0 ; j <= i ; j++)
            {
                sum += v_pos[j].fi.fi / cnt ;
                cnt++ ;
            }
            while(now < k)
            {
                ld mn = 1e9 ;
                if(uk1 < v_pos.size())
                    mn = v_pos[uk1].fi.se ;
                if(uk2 < v_neg.size())
                    mn = min(mn, v_neg[uk2].fi.fi) ;
                sum += mn / cnt ;
                if(uk1 < v_pos.size() && mn == v_pos[uk1].fi.se)
                    uk1++ ;
                else
                    uk2++ ;
                now++ ;
            }
            ans = min(ans, sum) ;
        }
        cout << fixed << setprecision(11) << ans ;
        return 0 ;
    }
    if(n <= 20)
    {
        ld ans = 1e9 ;
        for(int i = 1 ; i < (1 << n) ; i++)
            for(int j = 0 ; j < n ; j++)
                dp[i][j] = 1e9, cnt[i] += ((i & (1 << j)) > 0) ;
        dp[0][1] = 0 ;
        bfs() ;
        for(int i = 1 ; i < (1 << n) ; i++)
        {
            if(cnt[i] != k)
                continue ;
            for(int j = 0 ; j < k ; j++)
                ans = min(dp[i][j], ans) ;
        }
        cout << fixed << setprecision(11) << ans ;
        return 0 ;
    }
    return 0 ;
}

Compilation message (stderr)

Main.cpp: In function 'int main()':
Main.cpp:102:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<double, double>, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  102 |                 if(uk1 < v_pos.size())
      |                    ~~~~^~~~~~~~~~~~~~
Main.cpp:104:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<double, double>, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  104 |                 if(uk2 < v_neg.size())
      |                    ~~~~^~~~~~~~~~~~~~
Main.cpp:107:24: warning: comparison of integer expressions of different signedness: 'int' and 'std::vector<std::pair<std::pair<double, double>, int> >::size_type' {aka 'long unsigned int'} [-Wsign-compare]
  107 |                 if(uk1 < v_pos.size() && mn == v_pos[uk1].fi.se)
      |                    ~~~~^~~~~~~~~~~~~~

• Subtask 1: 5 / 5
• Subtask 2: 5 / 5
• Subtask 3: 0 / 11
• Subtask 4: 0 / 12
• Subtask 5: 0 / 33
• Subtask 6: 0 / 11
• Subtask 7: 0 / 23