Submission #554738

#	Time	Username	Problem	Language	Result	Execution time	Memory
554738		Jarif_Rahman	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	196 ms	32328 KiB

election_campaign

#include <bits/stdc++.h>
#define pb push_back
#define f first
#define sc second
using namespace std;
typedef long long int ll;
typedef string str;

const int K = 19;

struct BIT{
    int n;
    vector<ll> sm;
    BIT(){}
    BIT(int _n){
        n = _n;
        sm.resize(n);
    }
    void add(int in, ll x){
        in++;
        while(in <= n) sm[in-1]+=x, in+=in&-in;
    }
    void add(int l, int r, ll x){
        add(l, x);
        if(r+1 < n) add(r+1, -x);
    }
    ll get(int in){
        in++;
        ll s = 0;
        while(in >= 1) s+=sm[in-1], in-=in&-in;
        return s;
    }
};

int n, m;
vector<vector<int>> v;
vector<int> anc[K];
vector<int> depth;
vector<int> pos;
vector<int> sz;
int pos_cnt = 0;

int get_anc(int nd, int h){
    for(int i = 0; i < K; i++) { if(h%2 == 1) nd = anc[i][nd]; h/=2; } return nd;
}
int lca_jump(int a, int b){
    if(a == b) return a;
    for(int i = K-1; i >= 0; i--) if(anc[i][a] != anc[i][b])
        return lca_jump(anc[i][a], anc[i][b]);
    return anc[0][a];
}
int lca(int a, int b){
    if(depth[a] > depth[b]) swap(a, b);
    b = get_anc(b, depth[b]-depth[a]);
    return lca_jump(a, b);
}

void pre_dfs(int nd, int ss, int d){
    pos[nd] = pos_cnt++;
    for(int x: v[nd]) if(x != ss) pre_dfs(x, nd, d+1);
    for(int x: v[nd]) if(x != ss) sz[nd]+=sz[x];
    if(ss != -1) anc[0][nd] = ss;
    depth[nd] = d;
}

vector<vector<tuple<int, int, ll>>> plans;
vector<ll> dp, childsum;
BIT bit;

void dfs(int nd, int ss){
    for(int x: v[nd]) if(x != ss) dfs(x, nd);
    for(int x: v[nd]) if(x != ss) childsum[nd]+=dp[x];
    dp[nd] = childsum[nd];

    for(auto [a, b, c]: plans[nd]){
        ll cur = c;
        cur+=bit.get(pos[a]);
        cur+=bit.get(pos[b]);
        cur-=2LL*bit.get(pos[nd]);
        cur+=childsum[nd];
        dp[nd] = max(dp[nd], cur);
    }

    bit.add(pos[nd], pos[nd]+sz[nd]-1, childsum[nd]-dp[nd]);
}

int main(){
    ios_base::sync_with_stdio(0);
    cin.tie(0);

    cin >> n;
    v.assign(n, {});
    fill(anc, anc+K, vector<int>(n, 0));
    depth.assign(n, -1);
    pos.assign(n, -1);
    sz.assign(n, 1);
    plans.assign(n, {});
    dp.assign(n, 0);
    childsum.assign(n, 0);
    bit = BIT(n);

    for(int i = 0; i < n-1; i++){
        int a, b; cin >> a >> b; a--, b--;
        v[a].pb(b);
        v[b].pb(a);
    }

    pre_dfs(0, -1, 0);
    for(int p = 1; p < K; p++) for(int i = 0; i < n; i++)
        anc[p][i] = anc[p-1][anc[p-1][i]];

    cin >> m;

    for(int i = 0; i < m; i++){
        int a, b; ll c; cin >> a >> b >> c; a--, b--;
        plans[lca(a, b)].pb({a, b, c});
    }

    dfs(0, -1);

    cout << dp[0] << "\n";
}

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