oj.uz

Submission #197769

# Submission time Handle Problem Language Result Execution time Memory
197769 2020-01-22T22:29:57 Z DS007 Election Campaign (JOI15_election_campaign) C++14
10 / 100
 315 ms 40720 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[N];
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];
}

void solve(int v, int p = -1) {
    for (int i : adj[v]) {
        if (i != p) {
            solve(i, v);
            subtree[v] += dp[i];
            dp[v] += dp[i];
        }
    }

    for (auto i : q[v]) {
        long long sum = query_tree(1, 0, euler.size() - 1, first[v], first[i.a]) + query_tree(1, 0, euler.size() - 1, first[v], first[i.b]) + subtree[v] + i.c;
        dp[v] = max(dp[v], sum);
    }

    update(1, 0, euler.size() - 1, first[v], subtree[v] - dp[v]);
    if (v != 0)
        update(1, 0, euler.size() - 1, last[v] + 1, dp[v] - subtree[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);
    }

    dfs(0);
    build_sparse();

    cin >> m;
    for (int i = 0; i < m; i++) {
        int a, b, c;
        cin >> a >> b >> c;
        a--, b--;
        q[query_lca(a, b)].push_back({a, b, c});
    }
    // for (int i = 0; i < m; i++) cout << query_lca(q[i].a, q[i].b) << endl;

    solve(0);
    cout << *max_element(dp, dp + n);
}

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

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5112 KB Output is correct
4 Incorrect 7 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #2
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5368 KB Output is correct
4 Correct 235 ms 40588 KB Output is correct
5 Correct 238 ms 40656 KB Output is correct
6 Correct 220 ms 40544 KB Output is correct
7 Correct 242 ms 40616 KB Output is correct
8 Correct 239 ms 40672 KB Output is correct
9 Correct 231 ms 40720 KB Output is correct
10 Correct 247 ms 40548 KB Output is correct

Subtask #3
5.0 / 5.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5368 KB Output is correct
4 Correct 235 ms 40588 KB Output is correct
5 Correct 238 ms 40656 KB Output is correct
6 Correct 220 ms 40544 KB Output is correct
7 Correct 242 ms 40616 KB Output is correct
8 Correct 239 ms 40672 KB Output is correct
9 Correct 231 ms 40720 KB Output is correct
10 Correct 247 ms 40548 KB Output is correct
11 Correct 26 ms 5880 KB Output is correct
12 Correct 242 ms 40480 KB Output is correct
13 Correct 236 ms 40708 KB Output is correct
14 Correct 231 ms 40648 KB Output is correct
15 Correct 234 ms 40544 KB Output is correct
16 Correct 225 ms 40532 KB Output is correct
17 Correct 255 ms 40672 KB Output is correct
18 Correct 241 ms 40672 KB Output is correct
19 Correct 235 ms 40544 KB Output is correct
20 Correct 236 ms 40548 KB Output is correct

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 296 ms 32592 KB Output is correct
2 Correct 220 ms 40544 KB Output is correct
3 Incorrect 315 ms 37488 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5112 KB Output is correct
4 Incorrect 7 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -

Subtask #6
0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 7 ms 5112 KB Output is correct
4 Incorrect 7 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -