oj.uz

Submission #546591

# Submission time Handle Problem Language Result Execution time Memory
546591 2022-04-07T21:01:35 Z Olympia Lampice (COCI19_lampice) C++17
17 / 110
 5000 ms 15560 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>
#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")

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<vector<int>> adj;
    vector<int64_t> powr, ipowr;
    vector<vector<int>> dp;
    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) {
            int lg2 = log2(d);
            d -= (1 << lg2);
            l = dp[l][lg2];
        }
        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;
        dp[centroid].assign(dp[centroid].size(), 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), adj.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), dp.assign(n, (vector<int>)(17));
    }
};

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';
}

Compilation message

lampice.cpp:17: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   17 | #pragma GCC optimization ("O3")
      | 
lampice.cpp:18: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   18 | #pragma GCC optimization ("unroll-loops")
      |

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 340 KB Output is correct
2 Correct 14 ms 468 KB Output is correct
3 Correct 59 ms 596 KB Output is correct
4 Correct 62 ms 724 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct

Subtask #2
0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 4077 ms 13560 KB Output is correct
2 Correct 4113 ms 13864 KB Output is correct
3 Correct 2915 ms 14236 KB Output is correct
4 Correct 3535 ms 14924 KB Output is correct
5 Execution timed out 5084 ms 15560 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 5081 ms 13668 KB Time limit exceeded
2 Halted 0 ms 0 KB -

Subtask #4
0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 340 KB Output is correct
2 Correct 14 ms 468 KB Output is correct
3 Correct 59 ms 596 KB Output is correct
4 Correct 62 ms 724 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 1 ms 212 KB Output is correct
8 Correct 4077 ms 13560 KB Output is correct
9 Correct 4113 ms 13864 KB Output is correct
10 Correct 2915 ms 14236 KB Output is correct
11 Correct 3535 ms 14924 KB Output is correct
12 Execution timed out 5084 ms 15560 KB Time limit exceeded
13 Halted 0 ms 0 KB -