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Submission #546612

# Submission time Handle Problem Language Result Execution time Memory
546612 2022-04-07T21:22:17 Z Olympia Lampice (COCI19_lampice) C++17
17 / 110
 5000 ms 45668 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)4e5];
    vector<int64_t> powr, ipowr;
    int dp[(int)4e5][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)floor(log2(d & -d))];
            d -= (d & -d);
        }
        return l;
    }

    int centroid;
    int64_t get (int l, int r) {
        if (depth[l] < depth[r]) {
            return (dp1[r] - (powr[depth[r] - depth[l] + 1] * dp1[parent[l]]) % MOD + MOD) % MOD;
        } else {
            return (((dp2[l] - dp2[parent[r]] + MOD) % MOD) * (ipowr[depth[r]])) % 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) {
            if (dp1[go_up(curNode, max_len - depth[curNode] - 1)] == dp2[go_up(curNode, max_len - depth[curNode] - 1)]) {
                int64_t get_val = get(go_up(curNode, max_len - depth[curNode] - 2), curNode) + powr[max_len - depth[curNode] - 1] * s[centroid];
                get_val %= MOD;
                if (m1.count(get_val)) {
                    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;
    //cout << inv(BASE) << '\n';
}

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 36308 KB Output is correct
2 Correct 29 ms 36396 KB Output is correct
3 Correct 78 ms 36508 KB Output is correct
4 Correct 89 ms 36436 KB Output is correct
5 Correct 18 ms 36308 KB Output is correct
6 Correct 19 ms 36260 KB Output is correct
7 Correct 17 ms 36308 KB Output is correct

Subtask #2
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3995 ms 44480 KB Output is correct
2 Correct 4358 ms 44648 KB Output is correct
3 Correct 3155 ms 44896 KB Output is correct
4 Correct 3680 ms 45316 KB Output is correct
5 Execution timed out 5050 ms 45668 KB Time limit exceeded
6 Halted 0 ms 0 KB -

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5041 ms 43528 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 36308 KB Output is correct
2 Correct 29 ms 36396 KB Output is correct
3 Correct 78 ms 36508 KB Output is correct
4 Correct 89 ms 36436 KB Output is correct
5 Correct 18 ms 36308 KB Output is correct
6 Correct 19 ms 36260 KB Output is correct
7 Correct 17 ms 36308 KB Output is correct
8 Correct 3995 ms 44480 KB Output is correct
9 Correct 4358 ms 44648 KB Output is correct
10 Correct 3155 ms 44896 KB Output is correct
11 Correct 3680 ms 45316 KB Output is correct
12 Execution timed out 5050 ms 45668 KB Time limit exceeded
13 Halted 0 ms 0 KB -