Submission #206271

#	Time	Username	Problem	Language	Result	Execution time	Memory
206271		achibasadzishvili	Beads and wires (APIO14_beads)	C++17	0 / 100	15 ms	12280 KiB

beads

#include<bits/stdc++.h>
#define ll long long
#define f first
#define s second
#define pb push_back
#define mp make_pair
using namespace std;
ll n,dp[2][500005];
vector<pair<ll,ll> >v[500005];
void solve(ll x,ll par,ll dis){
    ll mx1 = -99999999999 , mx2 = -99999999999 , sum = 0;
    for(int i=0; i<v[x].size(); i++)
        if(v[x][i].f != par){
            ll to = v[x][i].f;
            solve(to , x , v[x][i].s);
            sum += max(dp[0][to] , dp[1][to]);
            ll cur = dp[0][to] + v[x][i].s - max(dp[0][to] , dp[1][to]);
            if(cur > mx1)mx2 = mx1 , mx1 = cur;
            else if(cur > mx2)mx2 = cur;
        }
    dp[0][x] = sum;
    if(v[x].size() - 1 + (x == 1) > 1)dp[0][x] = max(sum , sum + mx1 + mx2);
    if(x != 1 && v[x].size() > 1)
        dp[1][x] = sum + mx1 + dis;
    //cout << x << " " << dp[0][x] << " " << dp[1][x] << '\n';
}
int main(){
    ios::sync_with_stdio(false);
    cin >> n;
    
    for(int i=1; i<n; i++){
        ll x,y,z;
        cin >> x >> y >> z;
        v[x].pb(mp(y , z));
        v[y].pb(mp(x , z));
    }
    
    solve(1 , 0 , 0);
    dp[0][1] = max(0LL , dp[0][1]);
    cout << max(dp[0][1] , dp[1][1]) << '\n';
    
    
    return 0;
}

Compilation message (stderr)

beads.cpp: In function 'void solve(long long int, long long int, long long int)':
beads.cpp:12:19: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for(int i=0; i<v[x].size(); i++)
                  ~^~~~~~~~~~~~

• Subtask 1: 0 / 13
• Subtask 2: 0 / 15
• Subtask 3: 0 / 29
• Subtask 4: 0 / 43