oj.uz

Submission #546655

# Submission time Handle Problem Language Result Execution time Memory
546655 2022-04-07T23:34:32 Z Olympia Lampice (COCI19_lampice) C++17
42 / 110
 5000 ms 14204 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>
#include <ext/pb_ds/assoc_container.hpp>

#pragma GCC target ("avx2")
#pragma GCC optimization ("O3")
#pragma GCC optimization ("unroll-loops")
 
 
using namespace std;
 
const int MOD = 998244353;
const int BASE = 293;
const int inv = 705244304;
 
 
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;
 
    __gnu_pbds::gp_hash_table<int, bool> m1;
    vector<int> to_do;
    void dfs (int curNode, int prevNode) {
        if (depth[curNode] + 1 >= max_len) {
            return;
        }
        to_do.push_back(dp1[curNode]);
        for (int i: adj[curNode]) {
            if (i != prevNode && !hasVisited[i]) {
                dfs (i, 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.find(((dp1[curNode] - (powr[max_len - depth[curNode] - 1] * dp1[parent[x]]) % MOD + MOD) % MOD + powr[max_len - depth[curNode] - 1] * s[centroid]) % MOD) != m1.end()) {
                    fine ++;
                    return;
                }
            }
        }
    }
 
    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[j] = 1;
                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[j] = 1;
                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;
}

Compilation message

lampice.cpp:19: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   19 | #pragma GCC optimization ("O3")
      | 
lampice.cpp:20: warning: ignoring '#pragma GCC optimization' [-Wunknown-pragmas]
   20 | #pragma GCC optimization ("unroll-loops")
      |

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 4924 KB Output is correct
2 Correct 15 ms 4820 KB Output is correct
3 Correct 50 ms 4948 KB Output is correct
4 Correct 57 ms 5020 KB Output is correct
5 Correct 3 ms 4692 KB Output is correct
6 Correct 4 ms 4692 KB Output is correct
7 Correct 2 ms 4816 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 2828 ms 13340 KB Output is correct
2 Correct 2257 ms 13608 KB Output is correct
3 Correct 1488 ms 13596 KB Output is correct
4 Correct 1776 ms 13948 KB Output is correct
5 Correct 2744 ms 14204 KB Output is correct
6 Correct 320 ms 12680 KB Output is correct

Subtask #3
0 / 31.0

# Verdict Execution time Memory Grader output
1 Execution timed out 5034 ms 12524 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 4924 KB Output is correct
2 Correct 15 ms 4820 KB Output is correct
3 Correct 50 ms 4948 KB Output is correct
4 Correct 57 ms 5020 KB Output is correct
5 Correct 3 ms 4692 KB Output is correct
6 Correct 4 ms 4692 KB Output is correct
7 Correct 2 ms 4816 KB Output is correct
8 Correct 2828 ms 13340 KB Output is correct
9 Correct 2257 ms 13608 KB Output is correct
10 Correct 1488 ms 13596 KB Output is correct
11 Correct 1776 ms 13948 KB Output is correct
12 Correct 2744 ms 14204 KB Output is correct
13 Correct 320 ms 12680 KB Output is correct
14 Execution timed out 5034 ms 12524 KB Time limit exceeded
15 Halted 0 ms 0 KB -