oj.uz

Submission #546592

# Submission time Handle Problem Language Result Execution time Memory
546592 2022-04-07T21:03:20 Z Olympia Lampice (COCI19_lampice) C++17
42 / 110
 5000 ms 15592 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) {
            l = dp[l][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;
        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 500 KB Output is correct
3 Correct 55 ms 688 KB Output is correct
4 Correct 59 ms 788 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 3656 ms 13684 KB Output is correct
2 Correct 3572 ms 13864 KB Output is correct
3 Correct 2475 ms 14308 KB Output is correct
4 Correct 2996 ms 14920 KB Output is correct
5 Correct 4432 ms 15592 KB Output is correct
6 Correct 613 ms 15072 KB Output is correct

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5061 ms 13600 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 500 KB Output is correct
3 Correct 55 ms 688 KB Output is correct
4 Correct 59 ms 788 KB Output is correct
5 Correct 0 ms 212 KB Output is correct
6 Correct 0 ms 212 KB Output is correct
7 Correct 0 ms 212 KB Output is correct
8 Correct 3656 ms 13684 KB Output is correct
9 Correct 3572 ms 13864 KB Output is correct
10 Correct 2475 ms 14308 KB Output is correct
11 Correct 2996 ms 14920 KB Output is correct
12 Correct 4432 ms 15592 KB Output is correct
13 Correct 613 ms 15072 KB Output is correct
14 Execution timed out 5061 ms 13600 KB Time limit exceeded
15 Halted 0 ms 0 KB -