oj.uz

Submission #197793

# Submission time Handle Problem Language Result Execution time Memory
197793 2020-01-23T08:11:55 Z DS007 Election Campaign (JOI15_election_campaign) C++14
10 / 100
 305 ms 40672 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 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 6 ms 5116 KB Output is correct
4 Incorrect 6 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 7 ms 5240 KB Output is correct
4 Correct 223 ms 40580 KB Output is correct
5 Correct 227 ms 40604 KB Output is correct
6 Correct 218 ms 40544 KB Output is correct
7 Correct 220 ms 40548 KB Output is correct
8 Correct 224 ms 40548 KB Output is correct
9 Correct 210 ms 40672 KB Output is correct
10 Correct 221 ms 40448 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 7 ms 5240 KB Output is correct
4 Correct 223 ms 40580 KB Output is correct
5 Correct 227 ms 40604 KB Output is correct
6 Correct 218 ms 40544 KB Output is correct
7 Correct 220 ms 40548 KB Output is correct
8 Correct 224 ms 40548 KB Output is correct
9 Correct 210 ms 40672 KB Output is correct
10 Correct 221 ms 40448 KB Output is correct
11 Correct 21 ms 5880 KB Output is correct
12 Correct 230 ms 40516 KB Output is correct
13 Correct 234 ms 40608 KB Output is correct
14 Correct 224 ms 40544 KB Output is correct
15 Correct 228 ms 40544 KB Output is correct
16 Correct 221 ms 40580 KB Output is correct
17 Correct 231 ms 40544 KB Output is correct
18 Correct 228 ms 40544 KB Output is correct
19 Correct 229 ms 40620 KB Output is correct
20 Correct 229 ms 40520 KB Output is correct

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 279 ms 32556 KB Output is correct
2 Correct 219 ms 40504 KB Output is correct
3 Incorrect 305 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 6 ms 5112 KB Output is correct
2 Correct 6 ms 5112 KB Output is correct
3 Correct 6 ms 5116 KB Output is correct
4 Incorrect 6 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 6 ms 5116 KB Output is correct
4 Incorrect 6 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -