Submission #1112268

#	Time	Username	Problem	Language	Result	Execution time	Memory
1112268		huantran	Lampice (COCI19_lampice)	C++17	17 / 110	5059 ms	8272 KiB

lampice

#include <bits/stdc++.h>
 
using namespace std;
using ll = long long int;
const int maxn = 1e5 + 5;
const int oo = 1e9 + 7;
const ll inf = 1e18;
const int base = 37;
const int mod = 1e9 + 7;

int ans = 1;
int p[maxn];
int n;
string s;
vector<int> adj[maxn];

void dfs(int u, int par, int hash_up = 0, int hash_down = 0, int dep = 0) {
    hash_down = (1LL * base * hash_down + (s[u] - 'a' + 1)) % mod;
    hash_up = (1LL * hash_up + 1LL * (s[u] - 'a' + 1) * p[dep]) % mod;
    // cout << "Check: " << hash_down << ' ' << hash_up << '\n';
    if (hash_down == hash_up)
        ans = max(ans, dep + 1);
    
    for (auto j : adj[u]) {
        if (j == par)
            continue;
        dfs(j, u, hash_up, hash_down, dep + 1);
    }
}

int main() {
    ios_base::sync_with_stdio(0);
    cin.tie(0), cout.tie(0);
    
    p[0] = 1;
    for (int i = 1; i < maxn; i++)
        p[i] = (1LL * p[i - 1] * base) % mod;

    cin >> n;
    cin >> s;
    s = ' ' + s;
    for (int i = 1; i <= n - 1; i++) {
        int u, v;
        cin >> u >> v;
        adj[u].push_back(v);
        adj[v].push_back(u);
    }

    for (int i = 1; i <= n; i++) {
        dfs(i, i);
    }

    cout << ans;
}

• Subtask 1: 17 / 17
• Subtask 2: 0 / 25
• Subtask 3: 0 / 31
• Subtask 4: 0 / 37