Submission #1046189

#	Time	Username	Problem	Language	Result	Execution time	Memory
1046189		I_FloPPed21	Race (IOI11_race)	C++14	0 / 100	2 ms	21852 KiB

race

#include <bits/stdc++.h>

using namespace std;
map<int,int> mp[200005] ;
vector<pair<int,int>> adj[200005];
int h[200005][2], v[200005],target = 0,sum[200005],height[200005],ans = 1e9,n,k;

void precomp(int nod, int p, int hd)
{
    height[nod] = hd ;
    for ( auto u : adj[nod] )
    {
        if ( u.first != p )
        {
            sum[u.first] += sum[nod] + u.second;
            precomp(u.first,nod,hd + 1);
        }
    }
}

void small(int nod,int p )
{
    int real_target = target + 2 * sum[nod];
    for ( auto u : adj[nod] )
    {
        if ( u.first != p )
        {
            small(u.first,nod);
        }
    }

    for ( auto u : adj[nod] )
    {
        if( u.first != p )
        {
            if( mp[u.first].size() > mp[nod].size())
                swap(mp[nod],mp[u.first]);

            for ( auto k : mp[u.first] )
            {
                long long real = real_target - k.first ;

               /* if( nod == 6 && u.first == 8 )
                {
                    cout << real << '\n';
                }*/
                if ( mp[nod][real] != 0 )
                {
                    //cout << nod << " " << u.first << " " << k.first << " " << k.second << '\n';
                    ans = min ( long(ans), long(k.second + mp[nod][real] - 2 * height[nod]));
                }

                if( mp[nod][k.first] == 0 )
                    mp[nod][k.first] = k .second;
                else
                    mp[nod][k.first] = min(mp[nod][k.first],k.second);
            }
        }
    }

    /*if( nod == 6)
    {
        cout << mp[nod][real_target]<< '\n';
    }*/
    if( mp[nod][sum[nod]] == 0 )
        mp[nod][sum[nod]] = 1e11;
    mp[nod][sum[nod]] = min(height[nod],mp[nod][sum[nod]]);

    if( mp[nod][real_target-sum[nod]] != 0 )
        ans = min ( ans,mp[nod][real_target-sum[nod]] - height[nod]);


}
int best_path(int n, int k, int h[][2], int costs [] )
{
    target =k ;
    for ( int i = 1; i < n ; i ++ )
    {
        adj[h[i][1]].push_back({h[i][0],v[i]});
        adj[h[i][0]].push_back({h[i][1],v[i]});
    }
    for ( int i = 1; i < n ; i ++)
        v[i] =costs[i];

    precomp(0,-1,1);
    small(0,-1);

    if( mp[0][k] != 0 )
        ans = min ( ans, mp[0][k]);

    if( ans == 1e9)
        return -1;
    else
        return ans ;
}
/*int main()
{
    cin >> n >> k;
    for ( int i = 1; i < n ; i ++ )
    {
        cin >> h[i][0] >> h[i][1] >> v[i] ;
    }

    cout << best_path(n,k,h,v);

    return 0;
}*/

Compilation message (stderr)

race.cpp: In function 'void small(int, int)':
race.cpp:66:29: warning: overflow in conversion from 'double' to 'std::map<int, int>::mapped_type' {aka 'int'} changes value from '1.0e+11' to '2147483647' [-Woverflow]
   66 |         mp[nod][sum[nod]] = 1e11;
      |                             ^~~~

• Subtask 1: 0 / 9
• Subtask 2: 0 / 12
• Subtask 3: 0 / 22
• Subtask 4: 0 / 57