oj.uz

Submission #197791

# Submission time Handle Problem Language Result Execution time Memory
197791 2020-01-23T08:05:47 Z DS007 Election Campaign (JOI15_election_campaign) C++14
10 / 100
 307 ms 40676 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 << 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]*/0, first[i.a]) + query_tree(1, 0, euler.size() - 1, /*first[v]*/0, first[i.b]) + subtree[v] + i.c;
        dp[v] = max(dp[v], sum);
        // dp[v] = max(dp[v], subtree[v] + query_tree(1, 0, euler.size() - 1, first[v], first[i.a]) + i.c) + query_tree(1, 0, euler.size() - 1, first[v], first[i.b]);
    }

    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 7 ms 5112 KB Output is correct
2 Correct 6 ms 5116 KB Output is correct
3 Correct 6 ms 4984 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 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 8 ms 5368 KB Output is correct
4 Correct 225 ms 40484 KB Output is correct
5 Correct 227 ms 40544 KB Output is correct
6 Correct 216 ms 40544 KB Output is correct
7 Correct 226 ms 40608 KB Output is correct
8 Correct 228 ms 40544 KB Output is correct
9 Correct 218 ms 40548 KB Output is correct
10 Correct 226 ms 40648 KB Output is correct

Subtask #3
5.0 / 5.0

# 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 8 ms 5368 KB Output is correct
4 Correct 225 ms 40484 KB Output is correct
5 Correct 227 ms 40544 KB Output is correct
6 Correct 216 ms 40544 KB Output is correct
7 Correct 226 ms 40608 KB Output is correct
8 Correct 228 ms 40544 KB Output is correct
9 Correct 218 ms 40548 KB Output is correct
10 Correct 226 ms 40648 KB Output is correct
11 Correct 21 ms 5880 KB Output is correct
12 Correct 232 ms 40504 KB Output is correct
13 Correct 233 ms 40544 KB Output is correct
14 Correct 242 ms 40608 KB Output is correct
15 Correct 235 ms 40548 KB Output is correct
16 Correct 222 ms 40544 KB Output is correct
17 Correct 231 ms 40652 KB Output is correct
18 Correct 227 ms 40488 KB Output is correct
19 Correct 230 ms 40676 KB Output is correct
20 Correct 235 ms 40600 KB Output is correct

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 298 ms 32512 KB Output is correct
2 Correct 225 ms 40548 KB Output is correct
3 Incorrect 307 ms 37476 KB Output isn't correct
4 Halted 0 ms 0 KB -

Subtask #5
0 / 10.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 5112 KB Output is correct
2 Correct 6 ms 5116 KB Output is correct
3 Correct 6 ms 4984 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 7 ms 5112 KB Output is correct
2 Correct 6 ms 5116 KB Output is correct
3 Correct 6 ms 4984 KB Output is correct
4 Incorrect 7 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -