oj.uz

Submission #546631

# Submission time Handle Problem Language Result Execution time Memory
546631 2022-04-07T22:35:30 Z Olympia Lampice (COCI19_lampice) C++17
42 / 110
 5000 ms 13088 KB 
#include <cmath>
#include <iostream>
#include <set>
#include <climits>
#include <cstdio>
#include <algorithm>
#include <cassert>
#include <string>
#include <vector>
#include <iomanip>
#include <unordered_map>
#include <type_traits>
#include <string>
#include <queue>
#include <map>

using namespace std;

const int MOD = 1e9 + 9;
const int BASE = 293;
const int inv = 706484648;


class Tree {
public:
    vector<int> sub, depth, parent;
    vector<int64_t> dp1, dp2;
    vector<bool> hasVisited;
    vector<int> adj[(int)5e4];
    vector<int64_t> powr, ipowr;
    int dp[(int)5e4][17];
    string s;
    int sz;
    int dfs1 (int curNode, int prevNode) {
        sub[curNode] = 1;
        for (int i: adj[curNode]) if (!hasVisited[i] && i != prevNode) sub[curNode] += dfs1(i, curNode);
        return (sz = sub[curNode]);
    }
    int get_centroid (int curNode, int prevNode) {
        for (int i: adj[curNode]) if (!hasVisited[i] && i != prevNode && sub[i] > sz/2) return get_centroid(i, curNode);
        return curNode;
    }
    int max_len; int fine = 0;
    void fill (int curNode, int prevNode, int d, int64_t val1, int64_t val2) {
        dp1[curNode] = val1 = (BASE * val1 + s[curNode]) % MOD;
        dp2[curNode] = val2 = (powr[d] * s[curNode] + val2) % MOD;
        fine += (dp1[curNode] == dp2[curNode] && d + 1 == max_len);
        dp[curNode][0] = prevNode;
        for (int i = 1; i < 17; i++) {
            dp[curNode][i] = dp[dp[curNode][i - 1]][i - 1];
        }
        depth[curNode] = d;
        parent[curNode] = prevNode;
        for (int i: adj[curNode]) {
            if (!hasVisited[i] && i != prevNode) {
                fill(i, curNode, d + 1, val1, val2);
            }
        }
    }

    int64_t go_up (int l, int d) {
        while (d) {
            l = dp[l][(int)log2(d & -d)];
            d -= (d & -d);
        }
        return l;
    }

    int centroid;
    int get1 (int l, int r) {
        return (dp1[r] - (powr[depth[r] - depth[l] + 1] * dp1[parent[l]]) % MOD + MOD) % MOD;
    }

    set<int> m1;
    vector<int> to_do;
    void dfs (int curNode, int prevNode) {
        if (depth[curNode] + 1 >= max_len) {
            return;
        }
        to_do.push_back(dp1[curNode]);
        //m1[dp1[curNode]]++, v1[dp1[curNode]]++;
        if (2 * depth[curNode] + 1 >= max_len) {
            int x = go_up(curNode, max_len - depth[curNode] - 2);
            if (dp1[parent[x]] == dp2[parent[x]]) {
                if (m1.count((get1(x, curNode) + powr[max_len - depth[curNode] - 1] * s[centroid]) % MOD)) {
                    fine ++;
                    return;
                }
            }
        }
        for (int i: adj[curNode]) {
            if (i != prevNode && !hasVisited[i]) {
                dfs (i, curNode);
            }
        }
    }

    bool solve (int curNode) {
        dfs1(curNode, curNode);
        centroid = get_centroid(curNode, curNode);
        hasVisited[centroid] = true;
        depth[centroid] = 0;
        for (int i = 0; i < 17; i++) dp[centroid][i] = centroid;
        dp1[centroid] = s[centroid], dp2[centroid] = s[centroid];
        fine += (max_len == 1);
        for (int i: adj[centroid]) {
            if (!hasVisited[i]) {
                fill(i, centroid, 1, s[centroid], s[centroid]);
            }
        }
        m1.clear();
        for (int i: adj[centroid]) {
            if (!hasVisited[i]) {
                dfs (i, centroid);
                for (int j: to_do) m1.insert(j);
                to_do.clear();
            }
        }
        if (fine) return true;
        reverse(adj[centroid].begin(), adj[centroid].end());
        m1.clear();
        for (int i: adj[centroid]) {
            if (!hasVisited[i]) {
                dfs (i, centroid);
                for (int j: to_do) m1.insert(j);
                to_do.clear();
            }
        }
        if (fine) return true;
        for (int i: adj[centroid]) {
            if (!hasVisited[i]) {
                if (solve(i)) {
                    return true;
                }
            }
        }
        return false;
    }
    Tree (int n) {
        sub.resize(n), hasVisited.assign(n, false); powr.push_back(1); for (int i = 0; i <= n + 5; i++) powr.push_back(powr.back() * BASE), powr.back() %= MOD;
        ipowr.push_back(1); for (int i = 0; i <= n + 5; i++) ipowr.push_back(ipowr.back() * inv), powr.back() %= MOD;
        parent.resize(n), depth.resize(n), dp1.resize(n), dp2.resize(n);
    }
};

int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    int n; cin >> n;
    string s; cin >> s;
    Tree myTree(n);
    for (int i = 0; i < n - 1; i++) {
        int u, v;
        cin >> u >> v;
        u--, v--;
        myTree.adj[u].push_back(v), myTree.adj[v].push_back(u);
    }
    myTree.s = s;
    int myMax = 0;
    int l = 0;
    int r = s.length()/2;
    while (l != r) {
        int m = (l + r + 1)/2;
        myTree.max_len = 2 * m; myTree.fine = 0; myTree.hasVisited.assign(n, false);
        myTree.solve(0);
        if (myTree.fine) {
            l = m;
        } else {
            r = m - 1;
        }
    }
    myMax = max(myMax, 2 * l); l = 0;
    r = s.length()/2;
    while (l < r) {
        int m = (l + r + 1)/2;
        myTree.max_len = 2 * m + 1; myTree.fine = 0; myTree.hasVisited.assign(n, false);
        myTree.solve(0);
        if (myTree.fine) {
            l = m;
        } else {
            r = m - 1;
        }
    }
    myMax = max(myMax, 2 * l + 1);
    cout << myMax;
}

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4820 KB Output is correct
2 Correct 24 ms 4904 KB Output is correct
3 Correct 59 ms 4996 KB Output is correct
4 Correct 59 ms 5004 KB Output is correct
5 Correct 2 ms 4692 KB Output is correct
6 Correct 3 ms 4692 KB Output is correct
7 Correct 3 ms 4692 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3660 ms 11992 KB Output is correct
2 Correct 3595 ms 12136 KB Output is correct
3 Correct 2670 ms 12364 KB Output is correct
4 Correct 3463 ms 12728 KB Output is correct
5 Correct 4728 ms 13088 KB Output is correct
6 Correct 572 ms 11908 KB Output is correct

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5043 ms 11580 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4820 KB Output is correct
2 Correct 24 ms 4904 KB Output is correct
3 Correct 59 ms 4996 KB Output is correct
4 Correct 59 ms 5004 KB Output is correct
5 Correct 2 ms 4692 KB Output is correct
6 Correct 3 ms 4692 KB Output is correct
7 Correct 3 ms 4692 KB Output is correct
8 Correct 3660 ms 11992 KB Output is correct
9 Correct 3595 ms 12136 KB Output is correct
10 Correct 2670 ms 12364 KB Output is correct
11 Correct 3463 ms 12728 KB Output is correct
12 Correct 4728 ms 13088 KB Output is correct
13 Correct 572 ms 11908 KB Output is correct
14 Execution timed out 5043 ms 11580 KB Time limit exceeded
15 Halted 0 ms 0 KB -