Submission #1123050

#	Time	Username	Problem	Language	Result	Execution time	Memory
1123050		Mike_Vu	Election Campaign (JOI15_election_campaign)	C++20	100 / 100	116 ms	27468 KiB

election_campaign

#include <bits/stdc++.h>
using namespace std;
typedef long long ll;
typedef unsigned long long ull;
typedef long double dou;
#define pii pair<int, int>
#define fi first
#define se second
#define pb push_back
#define MASK(x) (1LL<<(x))
#define BITj(x, j) (((x)>>(j))&1)
#define ALL(v) (v).begin(), (v).end()

template<typename T> bool maximize(T &x, const T &y) {
    if (x < y) {x = y; return 1;}
    return 0;
}
template<typename T> bool minimize(T &x, const T &y) {
    if (x > y) {x = y; return 1;}
    return 0;
}

struct BIT{
    int n;
    vector<int> bit;
    void init(int _n = 0) {
        n = _n;
        bit.assign(n+1, 0);
    }
    void upd(int k, int x) {
        while (k <= n) {
            bit[k] += x;
            k += k & (-k);
        }
    }
    void update(int l, int r, int x) {
        upd(l, x);
        upd(r+1, -x);
    }
    int query(int k) {
        int res = 0;
        while (k > 0) {
            res += bit[k];
            k -= k & (-k);
        }
        return res;
    }
};

struct path{
    int u, v, c;
    path(int _u, int _v, int _c) {
        u = _u;
        v = _v;
        c = _c;
    }
};

const int maxn = 1e5+5, lg = 17;
int n, q;
vector<int> a[maxn];
vector<path> qu[maxn];
int tin[maxn], tout[maxn], par[maxn][lg], h[maxn], timer = 0;
int dp[maxn][2], pos[maxn];
BIT bit;

void dfspre(int u, int p) {
    tin[u] = ++timer;
    for (int j = 1; j < lg; j++) {
        if (h[u] <= MASK(j)) break;
        par[u][j] = par[par[u][j-1]][j-1];
    }
    for (int v : a[u]) {
        if (v == p) continue;
        par[v][0] = u;
        h[v] = h[u]+1;
        dfspre(v, u);
    }
    tout[u] = timer;
}
bool inside(int u, int v) {
    return (tin[v] <= tin[u] && tout[u] <= tout[v]);
}
int binlift(int u, int v) {
    for (int j = lg-1; j >= 0; j--) {
        while (h[u] > MASK(j) && !inside(v, par[u][j])) u = par[u][j];
    }
    return u;
}
int lca(int u, int v) {
    if (inside(u, v)) return v;
    if (inside(v, u)) return u;
    for (int j = lg-1; j >= 0; j--) {
        while (h[u] > MASK(j) && !inside(v, par[u][j])) u = par[u][j];
    }
    return par[u][0];
}

void dfssolve(int u, int p) {
    dp[u][0] = dp[u][1] = 0;
    int sz = a[u].size();
//    int ps[sz+1];
//    ps[0] = 0;
    for (int i = 1; i <= sz; i++) {
        int v = a[u][i-1];
//        ps[i] = ps[i-1];
        if (v == p) continue;
        dfssolve(v, u);
        pos[v] = i;
        dp[u][0] += max(dp[v][0], dp[v][1]);
//        ps[i] += max(dp[v][0], dp[v][1]);
    }
//    auto query = [&](int l, int r) {
//        l = max(1, l);
//        r = min(r, sz);
//        if (l > r) return 0;
//        return ps[r]-ps[l-1];
//    };
    //1
    for (path e : qu[u]) {
        int v1 = e.u, v2 = e.v, c = e.c;
        if (v1 == u) {
//            int p = pos[binlift(v2, u)];
//            int val = c+dp[v2][0]+query(1, p-1)+query(p+1, sz);
//            cout << u << ' ' << v2 << ' ' << c << ' ' << dp[u][0] << ' ' << bit.query(tin[v2]) << "\n";
            int val = c+dp[u][0]+bit.query(tin[v2]);
            maximize(dp[u][1], val);
        }
        else {
//            int l = pos[binlift(v1, u)], r = pos[binlift(v2, u)];
//            int val = c+dp[v1][0]+dp[v2][0]+query(1, l-1)+query(l+1, r-1)+query(r+1, sz);
            int val = c+dp[u][0]+bit.query(tin[v1])+bit.query(tin[v2]);
            maximize(dp[u][1], val);
        }
    }
    //update
    bit.update(tin[u], tout[u], dp[u][0]-max(dp[u][0], dp[u][1]));
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0);
    #define name "task"
//    if (fopen(name".inp", "r")) {
//        freopen(name".inp", "r", stdin);
//        freopen(name".out", "w", stdout);
//    }
    cin >> n;
    for (int i = 1; i < n; i++) {
        int u, v;
        cin >> u >> v;
        a[u].pb(v);
        a[v].pb(u);
    }
    h[1] = 1;
    dfspre(1, -1);
    bit.init(n);
    cin >> q;
    while (q--) {
        int u, v, c;
        cin >> u >> v >> c;
        if (tin[u] > tin[v]) swap(u, v);
        qu[lca(u, v)].pb(path(u, v, c));
    }
    dfssolve(1, -1);
//    for (int i = 1; i <= n; i++) {
//        cout << i << ' ' << dp[i][0] << ' ' << dp[i][1] << "\n";
//    }
    cout << max(dp[1][0], dp[1][1]);
}
/*
6
1 2
2 3
2 4
3 5
5 6
5
5 1 5
6 5 9
5 6 6
3 4 3
4 1 6
15

7
3 4
6 5
2 7
1 5
7 5
4 5
5
4 3 10
5 6 5
2 6 9
7 2 2
1 3 8
*/

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