oj.uz

답안 #197768

# 제출 시각 아이디 문제 언어 결과 실행 시간 메모리
197768 2020-01-22T22:09:50 Z DS007 Election Campaign (JOI15_election_campaign) C++14
10 / 100
 474 ms 35896 KB 
#include <bits/stdc++.h>
using namespace std;

struct query {
    int a, b, c;
};

const int N = 1e5;
vector<int> adj[N];
long long subtree[N], dp[N];
vector<query> q;
bool check[N];
int parent[N];
int n, m;

vector<int> euler, depth;
int first[N], last[N];
int c = 0;

int sparse[N * 2][18];
long long t[N * 8];

void dfs(int v, int p = -1, int d = 0) {
    first[v] = c++;
    parent[v] = p;
    euler.push_back(v);
    depth.push_back(d);

    for (int i : adj[v]) {
        if (i != p) {
            dfs(i, v, d + 1);
            euler.push_back(v);
            depth.push_back(d);
            c++;
        }
    }

    last[v] = c - 1;
}

int merge(int a, int b) {
    return depth[a] < depth[b] ? a : b;
}

void build_sparse() {
    for (int i = 0; i < euler.size(); i++)
        sparse[i][0] = i;

    for (int i = 1; i <= log2(n); i++) {
        for (int j = 0; j < euler.size() && j - 1 + (1 << i) < euler.size(); j++)
            sparse[j][i] = merge(sparse[j][i - 1], sparse[j + (1 << (i - 1))][i - 1]);
    }
}

int query_lca(int u, int v) {
    if (u == v) return u;
    int f1 = min(first[u], first[v]), f2 = max(first[v], first[u]), diff = f2 - f1;
    int dx = log2(diff);
    return euler[merge(sparse[f1][dx], sparse[f2 + 1 - (1 << dx)][dx])];
}

bool cmp(query u, query v) {
    int lca1 = query_lca(u.a, u.b), lca2 = query_lca(v.a, v.b);
    if (depth[first[lca1]] == depth[first[lca2]])
        return lca1 < lca2;
    return depth[first[lca1]] < depth[first[lca2]];
}

long long query_tree(int v, int l, int r, int tl, int tr) {
    if (tl > tr)
        return 0;
    else if (l == tl && r == tr)
        return t[v];

    int mid = (l + r) / 2;
    return query_tree(v * 2, l, mid, tl, min(mid, tr)) + query_tree(v * 2 + 1, mid + 1, r, max(tl, mid + 1), tr);
}

void update(int v, int l, int r, int tl, long long val) {
    if (l == r && l == tl) {
        t[v] = val;
        return;
    }

    int mid = (l + r) / 2;
    if (tl <= mid)
        update(v * 2, l, mid, tl, val);
    else
        update(v * 2 + 1, mid + 1, r, tl, val);

    t[v] = t[v * 2] + t[v * 2 + 1];
}

long long calc(int v, int p) {
    if (check[v])
        return dp[v];

    for (int i : adj[v]) {
        if (i != p)
            subtree[v] += calc(i, v);
    }
    dp[v] = subtree[v];

    check[v] = true;
    return dp[v];
}

long long solve(query u) {
    int lca = query_lca(u.a, u.b);
    if (!check[lca]) {
        calc(lca, parent[lca]);
    }

    long long sum = query_tree(1, 0, euler.size() - 1, first[lca], first[u.a]) + query_tree(1, 0, euler.size() - 1, first[lca], first[u.b]) + 2 * (dp[lca] - subtree[lca]) + subtree[lca] + u.c;
    if (sum > dp[lca]) {
        dp[lca] = sum;
        update(1, 0, euler.size() - 1, first[lca], subtree[lca] - dp[lca]);
        if (lca != 0)
            update(1, 0, euler.size() - 1, last[lca] + 1, dp[lca] - subtree[lca]);
    }

    assert(sum >= 0);
    return sum;
}

signed main() {
    ios::sync_with_stdio(false);
    cin.tie(nullptr);
    cout.tie(nullptr);

    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);
    }

    cin >> m;
    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        q.push_back({a, b, c});
    }

    dfs(0);
    build_sparse();
    // for (int i = 0; i < m; i++) cout << query_lca(q[i].a, q[i].b) << endl;
    sort(q.begin(), q.end(), &cmp);
    reverse(q.begin(), q.end());

    long long ans = 0;
    for (query i : q) {
        ans = max(ans, solve(i));
    }
    cout << ans;
}

Compilation message

election_campaign.cpp: In function 'void build_sparse()':
election_campaign.cpp:46:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < euler.size(); i++)
                     ~~^~~~~~~~~~~~~~
election_campaign.cpp:50:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < euler.size() && j - 1 + (1 << i) < euler.size(); j++)
                         ~~^~~~~~~~~~~~~~
election_campaign.cpp:50:62: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
         for (int j = 0; j < euler.size() && j - 1 + (1 << i) < euler.size(); j++)
                                             ~~~~~~~~~~~~~~~~~^~~~~~~~~~~~~~

Subtask #1
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2808 KB Output is correct
2 Correct 5 ms 2680 KB Output is correct
3 Correct 4 ms 2680 KB Output is correct
4 Incorrect 5 ms 3064 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2808 KB Output is correct
2 Correct 4 ms 2808 KB Output is correct
3 Correct 5 ms 3064 KB Output is correct
4 Correct 361 ms 35384 KB Output is correct
5 Correct 361 ms 35436 KB Output is correct
6 Correct 315 ms 35432 KB Output is correct
7 Correct 395 ms 35456 KB Output is correct
8 Correct 351 ms 35436 KB Output is correct
9 Correct 296 ms 35368 KB Output is correct
10 Correct 359 ms 35412 KB Output is correct

Subtask #3
5.0 / 5.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2808 KB Output is correct
2 Correct 4 ms 2808 KB Output is correct
3 Correct 5 ms 3064 KB Output is correct
4 Correct 361 ms 35384 KB Output is correct
5 Correct 361 ms 35436 KB Output is correct
6 Correct 315 ms 35432 KB Output is correct
7 Correct 395 ms 35456 KB Output is correct
8 Correct 351 ms 35436 KB Output is correct
9 Correct 296 ms 35368 KB Output is correct
10 Correct 359 ms 35412 KB Output is correct
11 Correct 45 ms 3700 KB Output is correct
12 Correct 362 ms 35652 KB Output is correct
13 Correct 357 ms 35636 KB Output is correct
14 Correct 313 ms 35808 KB Output is correct
15 Correct 380 ms 35816 KB Output is correct
16 Correct 306 ms 35896 KB Output is correct
17 Correct 364 ms 35720 KB Output is correct
18 Correct 365 ms 35836 KB Output is correct
19 Correct 312 ms 35688 KB Output is correct
20 Correct 391 ms 35724 KB Output is correct

Subtask #4
0 / 30.0

# 결과 실행 시간 메모리 Grader output
1 Correct 410 ms 30060 KB Output is correct
2 Correct 318 ms 35372 KB Output is correct
3 Incorrect 474 ms 35692 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2808 KB Output is correct
2 Correct 5 ms 2680 KB Output is correct
3 Correct 4 ms 2680 KB Output is correct
4 Incorrect 5 ms 3064 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #6
0 / 40.0

# 결과 실행 시간 메모리 Grader output
1 Correct 4 ms 2808 KB Output is correct
2 Correct 5 ms 2680 KB Output is correct
3 Correct 4 ms 2680 KB Output is correct
4 Incorrect 5 ms 3064 KB Output isn't correct
5 Halted 0 ms 0 KB -