Submission #1296271

#	Time	Username	Problem	Language	Result	Execution time	Memory
1296271		jahongir	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	113 ms	30232 KiB

election_campaign

#pragma GCC optimize("O3")
#pragma GCC optimize("unroll-loops")

#include <bits/stdc++.h>
#include <ext/pb_ds/assoc_container.hpp>
#include <ext/pb_ds/tree_policy.hpp>
 
using namespace std;
using namespace __gnu_pbds;
 
template<typename T> using ordered_set = tree<T,null_type,less<T>,rb_tree_tag,
					 tree_order_statistics_node_update>;

#define ll long long
#define pi pair<int,int>
#define vi vector<int>
#define pb push_back
#define all(a) a.begin(),a.end()  

const int mxn = 1e5+1, lg2 = 17;
vector<int> g[mxn];
int suc[mxn][lg2];
int tin[mxn],tout[mxn],tim = 0;


void pre_dfs(int u, int p){
    tin[u] = ++tim;
    for(int i = 1; i < lg2; i++)
        suc[u][i] = suc[suc[u][i-1]][i-1];
    for(auto v : g[u]) if(v!=p){
        suc[v][0] = u; pre_dfs(v,u);
    }
    tout[u] = tim;
}

bool is_anc(int u, int v){
    return tin[u]<=tin[v] && tout[v]<=tout[u];
}

int get_lca(int u, int v){
    if(is_anc(u,v)) return u;
    if(is_anc(v,u)) return v;
    for(int i = lg2-1; i >= 0; i--)
        if(!is_anc(suc[u][i],v))
            u = suc[u][i];
    return suc[u][0];
}


ll dp[mxn], bit[mxn];
vector<array<int,3>> qu[mxn];

void add(int i, ll val){
    for(; i < mxn; i+=i&-i)
        bit[i] += val;
}

ll get(int i){
    ll res = 0;
    for(; i > 0; i-=i&-i)
        res += bit[i];
    return res;
}


int get2(int u, int v){
    if(u==v) return u;
    for(int i = lg2-1; i >= 0; i--){
        if(tin[u] < tin[suc[v][i]])
            v = suc[v][i];
    }
    return v;
}

void dfs(int u, int p){
    ll sum = 0;
    for(auto v : g[u]) if(v!=p){
        dfs(v,u); sum += dp[v];
    }



    ll mx = sum;
    for(auto [x,y,c] : qu[u]){
        ll tmp = sum - dp[get2(u,x)] - dp[get2(u,y)] + get(tin[x]) + get(tin[y]) + c;
        mx = max(mx,tmp);
    }


    for(auto v : g[u]) if(v!=p){
        add(tin[v],sum-dp[v]);
        add(tout[v]+1,dp[v]-sum);
    }

    dp[u] = mx;


    add(tin[u],sum);
    add(tin[u]+1,-sum);

}



void solve(){
    int n,m; cin >> n;
    for(int i = 1; i < n; i++){
        int u,v; cin >> u >> v;
        g[u].pb(v); g[v].pb(u);
    }
    suc[1][0] = 1; pre_dfs(1,1);

    cin >> m;
    for( int i = 0; i < m; i++){
        int u,v,c; cin >> u >> v >> c;
        if(tin[u]>tin[v]) swap(u,v);
        qu[get_lca(u,v)].push_back({u,v,c});
    }

    dfs(1,1);

    cout << dp[1];
}




signed main(){
    cin.tie(0)->sync_with_stdio(0);
    int t = 1;
    // cin >> t;
    while(t--){solve();}
}

• Subtask 1: 10 / 10
• Subtask 2: 5 / 5
• Subtask 3: 5 / 5
• Subtask 4: 30 / 30
• Subtask 5: 10 / 10
• Subtask 6: 40 / 40