Submission #906732

#	Time	Username	Problem	Language	Result	Execution time	Memory
906732		box	Election Campaign (JOI15_election_campaign)	C++17	100 / 100	126 ms	31060 KiB

election_campaign

#include <bits/stdc++.h>
using namespace std;

#ifdef LOCAL
template <class T, class... U> void bug_h(const T& t, const U&... u) { cerr << t; ((cerr << " | " << u), ...); cerr << endl; }
#define bug(...) cerr << "L" << __LINE__ << " [" << #__VA_ARGS__ << "]: ", bug_h(__VA_ARGS__)
#else
#define cerr if (0) cerr
#define bug(...)
#endif

#define ar array
#define all(v) std::begin(v), std::end(v)
#define sz(v) int(std::size(v))
typedef long long i64;
typedef vector<int> vi;
typedef pair<int, int> pi;

const int MAXN = 1e5;

int N;
vi adj[MAXN];
int depth[MAXN], jmp[MAXN][17], tin[MAXN], tout[MAXN], tt;
vector<ar<int, 3>> paths[MAXN];
i64 dp[MAXN], dq[MAXN];

struct {
    i64 t[MAXN];
    void add(int i, i64 x) {
        while (i < MAXN) {
            t[i] += x;
            i |= i+1;
        }
    }
    i64 qry(int i) {
        i64 x = 0;
        while (i >= 0) {
            x += t[i];
            i &= i+1, i--;
        }
        return x;
    }
    void add(int l, int r, i64 x) {
        add(l, x), add(r+1, -x);
    }
} T;

void dfs(int i) {
    tin[i] = tt++;
    for (int l = 1; l < 17; l++) jmp[i][l] = jmp[jmp[i][l-1]][l-1];
    for (int j : adj[i]) if (jmp[i][0]^j) {
        depth[j] = depth[i]+1;
        jmp[j][0] = i;
        dfs(j);
    }
    tout[i] = tt-1;
}

int jump(int i, int d) {
    for (int l = 0; l < 17; l++) if (d>>l&1) i = jmp[i][l];
    return i;
}

int lca(int i, int j) {
    if (depth[i] < depth[j]) swap(i, j);
    i = jump(i, depth[i]-depth[j]);
    if (i == j) return i;
    for (int l = 16; l >= 0; l--) if (jmp[i][l]^jmp[j][l]) i = jmp[i][l], j = jmp[j][l];
    return jmp[i][0];
}

void rec(int i) {
    for (int j : adj[i]) if (jmp[i][0]^j) rec(j);
    for (int j : adj[i]) if (jmp[i][0]^j) {
        T.add(tin[i]+1, tout[i], dp[j]);
        T.add(tin[j], tout[j], -dp[j]);
        dq[i] += dp[j];
    }
    dp[i] = dq[i];
    for (auto [x, y, w] : paths[i])
        if (x^i) dp[i] = max(dp[i], w+T.qry(tin[x])+T.qry(tin[y])-dq[i]+dq[x]+dq[y]);
        else dp[i] = max(dp[i], w+T.qry(tin[y])+dq[y]);
}


int main() {
    ios::sync_with_stdio(0); cin.tie(0);
    cin >> N;
    for (int i = 0; i < N-1; i++) {
        int x, y; cin >> x >> y, x--, y--;
        adj[x].push_back(y);
        adj[y].push_back(x);
    }
    jmp[0][0] = 0;
    dfs(0);
    int M; cin >> M;
    while (M--) {
        int x, y, w; cin >> x >> y >> w, x--, y--;
        if (depth[x] > depth[y]) swap(x, y);
        int z = lca(x, y);
        paths[z].push_back({x, y, w});
    }
    rec(0);
    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