Submission #1125890

#	Time	Username	Problem	Language	Result	Execution time	Memory
1125890		TVSown	Lampice (COCI19_lampice)	C++20	17 / 110	5109 ms	353808 KiB

lampice

///*** Sown_Vipro ***///
/// ->TUYEN QUOC GIA<- ///

#include<bits/stdc++.h>
using namespace std;
//#pragma GCC optimize ("O3")
//#pragma GCC optimize ("unroll-loops")
//#pragma GCC target("popcnt")
#define F first
#define S second
#define pb push_back
#define pi pair<int, int>
#define pii pair<int, pair<int, int> >
#define all(a) a.begin(), a.end()
#define FOR(i, a, b) for(int i = a; i <= b; ++i)
#define REP(i, a, b) for(int i = a; i >= b; --i)
#define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
#define out(name) if(fopen(name, "w")) freopen(name, "w", stdout);

const int N = 1e6 + 5, MAX = 1e6, oo = 1e9 + 5, MOD = 1e9 + 7, base = 311;
int n, res, ans;
int s[N], del[N], pw[N];
string str;
vector<int> e[N];
map<int, int> f[N];
void count_child(int u, int p){
    s[u] = 1;
    for(int v : e[u]){
        if(v != p && !del[v]){
            count_child(v, u);
            s[u] += s[v];
        }
    }
}

int find_centroid(int u, int p, int n){
    for(int v : e[u]){
        if(v != p && !del[v] && s[v] > n) return find_centroid(v, u, n);
    }
    return u;
}

void dfs(int u, int p, int k, int h, int up, int down, int type){
    if(k < h) return;
    down = (1ll * down * base + str[u]) % MOD;
    up = (1ll * str[u] * pw[h - 1] + up) % MOD;
    int x = (1ll * up * pw[k - h] - down + MOD) % MOD;

    if(type <= 1) f[h - 1][x] = type;
    else res = max(res, k * f[k - h][x]);

    for(int v : e[u]){
        if(v != p && !del[v]){
            dfs(v, u, k, h + 1, up, down, type);
        }
    }
}

void build(int u, int k){
    count_child(u, 0);
    int cen = find_centroid(u, 0, s[u] / 2);
    del[cen] = 1;
    int x = (-str[cen] + MOD) % MOD;
    f[0][x] = 1;
    for(int v : e[cen]){
        if(del[v]) continue;

        dfs(v, cen, k, 2, 0, str[cen], 2);
        dfs(v, cen, k, 2, 0, str[cen], 1);
    }
    f[0][x] = 0;
    for(int v : e[cen]){
        if(del[v]) continue;

        dfs(v, cen, k, 2, 0, str[cen], 0);
    }

    if(res == k) return;
    for(int v : e[cen]){
        if(!del[v]) build(v, k);
    }
}

void solve(){
    cin >> n;
    cin >> str;
    str = "#" + str;
    FOR(i, 2, n){
        int u, v; cin >> u >> v;
        e[u].pb(v);
        e[v].pb(u);
    }
    pw[0] = 1;
    FOR(i, 1, n) pw[i] = (1ll * pw[i - 1] * base) % MOD;


    int l = 1, r = n; ans = 1;
    while(l <= r){
        int mid = (l + r) / 2;
        FOR(u, 1, n) del[u] = 0;
        res = 1;
        build(1, mid * 2);

        if(res == mid * 2){
            l = mid + 1;
            ans = max(ans, res);
        }else r = mid - 1;
    }
    l = 1; r = n;
    while(l <= r){
        int mid = (l + r) / 2;
        FOR(u, 1, n) del[u] = 0;
        res = 1;
        build(1, mid * 2 + 1);

        if(res == mid * 2 + 1){
            l = mid + 1;
            ans = max(ans, res);
        }else r = mid - 1;
    }
    cout << ans;
}

signed main(){
    ios_base::sync_with_stdio(false);
    cin.tie(0); cout.tie(0);
    inp("in.txt");
//    out("out.txt");
    int t = 1;
//    cin >> t;
    while(t--){
        solve();
    }
}

Compilation message (stderr)

lampice.cpp: In function 'int main()':
lampice.cpp:17:47: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)' declared with attribute 'warn_unused_result' [-Wunused-result]
   17 | #define inp(name) if(fopen(name, "r")) freopen(name, "r", stdin);
      |                                        ~~~~~~~^~~~~~~~~~~~~~~~~~
lampice.cpp:127:5: note: in expansion of macro 'inp'
  127 |     inp("in.txt");
      |     ^~~

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