oj.uz

Submission #197790

# Submission time Handle Problem Language Result Execution time Memory
197790 2020-01-23T07:56:09 Z DS007 Election Campaign (JOI15_election_campaign) C++14
10 / 100
 328 ms 43364 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], 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);
        // 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 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 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 235 ms 42976 KB Output is correct
5 Correct 240 ms 43136 KB Output is correct
6 Correct 228 ms 42996 KB Output is correct
7 Correct 244 ms 42948 KB Output is correct
8 Correct 241 ms 42948 KB Output is correct
9 Correct 228 ms 42928 KB Output is correct
10 Correct 237 ms 43016 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 235 ms 42976 KB Output is correct
5 Correct 240 ms 43136 KB Output is correct
6 Correct 228 ms 42996 KB Output is correct
7 Correct 244 ms 42948 KB Output is correct
8 Correct 241 ms 42948 KB Output is correct
9 Correct 228 ms 42928 KB Output is correct
10 Correct 237 ms 43016 KB Output is correct
11 Correct 23 ms 6136 KB Output is correct
12 Correct 239 ms 43244 KB Output is correct
13 Correct 240 ms 43232 KB Output is correct
14 Correct 226 ms 43360 KB Output is correct
15 Correct 236 ms 43276 KB Output is correct
16 Correct 226 ms 43236 KB Output is correct
17 Correct 248 ms 43304 KB Output is correct
18 Correct 234 ms 43364 KB Output is correct
19 Correct 223 ms 43360 KB Output is correct
20 Correct 245 ms 43268 KB Output is correct

Subtask #4
0 / 30.0

# Verdict Execution time Memory Grader output
1 Correct 308 ms 35028 KB Output is correct
2 Correct 222 ms 42948 KB Output is correct
3 Incorrect 328 ms 39904 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 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 6 ms 5112 KB Output is correct
4 Incorrect 7 ms 5368 KB Output isn't correct
5 Halted 0 ms 0 KB -