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Submission #1115822

# Submission time Handle Problem Language Result Execution time Memory
1115822 2024-11-21T02:01:43 Z ljtunas Lampice (COCI19_lampice) C++14
110 / 110
 1756 ms 90444 KB 
// author : anhtun_hi , nqg
#include <bits/stdc++.h>
#define ll long long
#define ii pair<ll, ll>
#define fi first
#define se second
#define all(x) x.begin(), x.end()
#define reset(h, v)    memset(h, v, sizeof h)
#define Forv(i, a)     for(auto& i : a)
#define For(i, a, b)   for(int i = a; i <= b; ++i)
#define Ford(i, a, b)  for(int i = a; i >= b; --i)
#define c_bit(i)     __builtin_popcountll(i)
#define Bit(mask, i)    ((mask >> i) & 1LL)
#define onbit(mask, i)  ((mask) bitor (1LL << i))
#define offbit(mask, i) ((mask) &~ (1LL << i))
#define TIME (1.0 * clock() / CLOCKS_PER_SEC)
using namespace std;
namespace std {
    template <typename T, int D>
    struct _vector : public vector <_vector <T, D - 1>> {
        static_assert(D >= 1, "Dimension must be positive!");
        template <typename... Args>
        _vector(int n = 0, Args... args) : vector <_vector <T, D - 1>> (n, _vector <T, D - 1> (args...)) {}
    };
    template <typename T> struct _vector <T, 1> : public vector <T> {
        _vector(int n = 0, const T& val = T()) : vector <T> (n, val) {}
    };
    template <class A, class B> bool minimize(A &a, B b){return a > b ? a = b, true : false;}
    template <class A, class B> bool maximize(A &a, B b){return a < b ? a = b, true : false;}
}
const int dx[] = {0, 0, +1, -1}, dy[] = {-1, +1, 0, 0}, LOG = 20, base = 311, inf = 1e9 + 5;
const int MAXN = 1e6 + 5;
const  ll  mod = 1e9 + 7;
const  ll   oo = 1e18;

//#define int long long

int n; vector<int> g[MAXN];
string s;
ll p[MAXN];

int sz[MAXN]; ll h[MAXN]; bool del[MAXN];

void dfsSize(int u, int par){
    sz[u] = 1;
    Forv(v, g[u]) if(v != par && !del[v]) dfsSize(v, u), sz[u] += sz[v];
}

int find(int u, int par, int n){
    Forv(v, g[u]) if(v != par && !del[v] && sz[v] * 2 > n) return find(v, u, n);
    return u;
}

ll mxhigh = 0, mxlen;
ll hashup[MAXN], hashdown[MAXN], a[MAXN];
map<ll, bool> mp[MAXN]; bool op;


vector<int> List;
void add(int u, int par){
    if(op) return;
    h[u] = h[par] + 1;
    if (h[u] + 1 > mxlen) return;
    maximize(mxhigh, h[u]);
    hashup[u] = (hashup[par] * base + s[u] - 'a' + 1) % mod;
    hashdown[u] = (hashdown[par] + p[h[u]] * (s[u] - 'a' + 1)) % mod;
    ll cur = (1LL * p[mxlen - h[u] - 1] * hashdown[u] - hashup[u] + mod) % mod;
    if (mp[mxlen - h[u] - 1].find(cur) != mp[mxlen - h[u] - 1].end()){
        op = true;
        return;
    }
    if (h[u] + 1 == mxlen && hashdown[u] == (hashup[u] + p[h[u]] * (s[u] - 'a' + 1)) % mod){
        op = true;
        return;
    }
    a[u] = cur, List.push_back(u);
    Forv(v, g[u]) if(v != par && !del[v]) add(v, u);
}

void solve(int u, int par){
    if(op) return;
    dfsSize(u, par);
    int centroid = find(u, par, sz[u]);
    del[centroid] = true;
    mxhigh = 0, h[centroid] = 0, hashup[centroid] = 0, hashdown[centroid] = s[centroid] - 'a' + 1;
    Forv(v, g[centroid]) if(v != par && !del[v]){
        add(v, centroid);
        Forv(i, List) mp[h[i]][a[i]] = true;
        List.clear();
    }
    For(i, 0, mxhigh) mp[i].clear();
    Forv(v, g[centroid]) if(v != par && !del[v]) solve(v, centroid);
}

bool check(int val){
    reset(del, 0);
    op = false; mxlen = val;
    solve(1, 0);
    return op;
}

void Solve() {
    cin >> n >> s;
    s = ' ' + s;
    For(i, 1, n - 1){
        int u, v; cin >> u >> v;
        g[u].push_back(v);
        g[v].push_back(u);
    }
    p[0] = 1;
    For(i, 1, n) p[i] = p[i - 1] * base % mod;
    int ans = 1;
    For(_, 0, 1){
        int l = 0, r = n / 2 + 1;
        while(r - l > 1){
            int mid = l + r >> 1;
            if(check(mid * 2 + _)) l = mid;
            else r = mid;
        }
        maximize(ans, _ + l * 2);
    }
    cout << ans << '\n';
}

signed main() {
    cin.tie(0) -> sync_with_stdio(0);
    if(fopen("noel.inp", "r")) {
        freopen("noel.inp", "r", stdin);
        freopen("noel.out", "w", stdout);
    }

    int t = 1;
//    cin >> t;
    while(t --) Solve();

    return 0;
}

Compilation message

lampice.cpp: In function 'void Solve()':
lampice.cpp:116:25: warning: suggest parentheses around '+' inside '>>' [-Wparentheses]
  116 |             int mid = l + r >> 1;
      |                       ~~^~~
lampice.cpp: In function 'int main()':
lampice.cpp:128:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  128 |         freopen("noel.inp", "r", stdin);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~
lampice.cpp:129:16: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
  129 |         freopen("noel.out", "w", stdout);
      |         ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 82000 KB Output is correct
2 Correct 19 ms 82348 KB Output is correct
3 Correct 29 ms 82264 KB Output is correct
4 Correct 28 ms 82000 KB Output is correct
5 Correct 15 ms 73808 KB Output is correct
6 Correct 15 ms 82000 KB Output is correct
7 Correct 13 ms 82000 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 681 ms 89424 KB Output is correct
2 Correct 670 ms 89460 KB Output is correct
3 Correct 467 ms 89808 KB Output is correct
4 Correct 586 ms 90304 KB Output is correct
5 Correct 881 ms 90444 KB Output is correct
6 Correct 110 ms 89024 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 1477 ms 88148 KB Output is correct
2 Correct 1709 ms 88000 KB Output is correct
3 Correct 1430 ms 88024 KB Output is correct
4 Correct 1260 ms 86804 KB Output is correct
5 Correct 1191 ms 87504 KB Output is correct
6 Correct 1115 ms 86876 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 82000 KB Output is correct
2 Correct 19 ms 82348 KB Output is correct
3 Correct 29 ms 82264 KB Output is correct
4 Correct 28 ms 82000 KB Output is correct
5 Correct 15 ms 73808 KB Output is correct
6 Correct 15 ms 82000 KB Output is correct
7 Correct 13 ms 82000 KB Output is correct
8 Correct 681 ms 89424 KB Output is correct
9 Correct 670 ms 89460 KB Output is correct
10 Correct 467 ms 89808 KB Output is correct
11 Correct 586 ms 90304 KB Output is correct
12 Correct 881 ms 90444 KB Output is correct
13 Correct 110 ms 89024 KB Output is correct
14 Correct 1477 ms 88148 KB Output is correct
15 Correct 1709 ms 88000 KB Output is correct
16 Correct 1430 ms 88024 KB Output is correct
17 Correct 1260 ms 86804 KB Output is correct
18 Correct 1191 ms 87504 KB Output is correct
19 Correct 1115 ms 86876 KB Output is correct
20 Correct 1061 ms 85492 KB Output is correct
21 Correct 1466 ms 86568 KB Output is correct
22 Correct 1756 ms 86916 KB Output is correct
23 Correct 381 ms 84304 KB Output is correct
24 Correct 1142 ms 85840 KB Output is correct
25 Correct 1031 ms 85488 KB Output is correct
26 Correct 1353 ms 87500 KB Output is correct
27 Correct 1682 ms 87324 KB Output is correct
28 Correct 769 ms 84556 KB Output is correct
29 Correct 792 ms 84584 KB Output is correct
30 Correct 998 ms 86344 KB Output is correct
31 Correct 837 ms 85228 KB Output is correct
32 Correct 919 ms 87368 KB Output is correct
33 Correct 1035 ms 86856 KB Output is correct