Submission #1088812

#	Time	Username	Problem	Language	Result	Execution time	Memory
1088812		TrinhKhanhDung	Election Campaign (JOI15_election_campaign)	C++14	100 / 100	129 ms	31132 KiB

election_campaign

#include <bits/stdc++.h>
#define ll long long
#define fi first
#define se second
#define sz(x) (int)x.size()
#define ALL(v) v.begin(),v.end()
#define MASK(k) (1LL << (k))
#define BIT(x, i) (((x) >> (i)) & 1)
#define oo (ll)1e18
#define INF (ll)1e9
#define MOD (ll)(1e9 + 7)

using namespace std;

template<class T1, class T2>
    bool maximize(T1 &a, T2 b){if(a < b){a = b; return true;} return false;}

template<class T1, class T2>
    bool minimize(T1 &a, T2 b){if(a > b){a = b; return true;} return false;}

template<class T1, class T2>
    void add(T1 &a, T2 b){a += b; if(a >= MOD) a -= MOD;}

template<class T1, class T2>
    void sub(T1 &a, T2 b){a -= b; if(a < 0) a += MOD;}

template<class T>
    void cps(T &v){sort(ALL(v)); v.resize(unique(ALL(v)) - v.begin());}

struct fen{
    vector<ll> tree;
    int n;

    fen(int _n = 0){
        n = _n;
        tree.resize(n + 3, 0);
    }

    void upd(int p, ll c){
        while(p <= n){
            tree[p] += c;
            p += p & -p;
        }
    }

    ll get(int p){
        ll ans = 0;
        while(p){
            ans += tree[p];
            p -= p & -p;
        }
        return ans;
    }
} bit0, bit1;

const int MAX = 1e5 + 10, LOG = 17;

int N, M;
vector<int> adj[MAX];
int h[MAX], d[MAX][LOG], f[MAX][2], timer, in[MAX], out[MAX];
vector<array<int, 3>> plans[MAX];

void dfs(int u, int p = -1){
    in[u] = ++timer;
    for(int v: adj[u]){
        if(v == p) continue;
        h[v] = h[u] + 1;
        d[v][0] = u;
        for(int i = 1; i < LOG; i++) d[v][i] = d[d[v][i - 1]][i - 1];
        dfs(v, u);
    }
    out[u] = timer;
}

int lca(int u, int v){
    if(h[u] < h[v]) swap(u, v);
    int delta = h[u] - h[v];
    for(int i = 0; i < LOG; i++) if(BIT(delta, i)){
        u = d[u][i];
    }
    if(u == v) return u;
    for(int i = LOG - 1; i >= 0; i--) if(d[u][i] != d[v][i]){
        u = d[u][i];
        v = d[v][i];
    }
    return d[u][0];
}

void dfs2(int u, int p = -1){
    for(int v: adj[u]){
        if(v == p) continue;
        dfs2(v, u);
        f[u][0] += f[v][1];
    }
    bit0.upd(in[u], f[u][0]);
    bit0.upd(out[u] + 1, -f[u][0]);
    f[u][1] = f[u][0];
    for(auto o: plans[u]){
        int a = o[0], b = o[1], c = o[2];
        ll sum = bit0.get(in[a]) + bit0.get(in[b]) - bit0.get(in[u]) - bit1.get(in[a]) - bit1.get(in[b]);
        maximize(f[u][1], sum + c);
    }
    bit1.upd(in[u], f[u][1]);
    bit1.upd(out[u] + 1, -f[u][1]);
}

void solve(){
    cin >> N;
    for(int i = 1; i < N; i++){
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }
    dfs(1);
    cin >> M;
    for(int i = 1; i <= M; i++){
        int u, v, c;
        cin >> u >> v >> c;
        int p = lca(u, v);
        plans[p].push_back({u, v, c});
    }
    bit0 = fen(N);
    bit1 = fen(N);
    dfs2(1);
    ll ans = 0;
    for(int i = 1; i <= N; i++) maximize(ans, f[i][1]);
    cout << ans << '\n';
}

int main(){
    ios_base::sync_with_stdio(0); cin.tie(0);
    // freopen("order.inp","r",stdin);
    // freopen("order.out","w",stdout);

    solve();

    return 0;
}

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