oj.uz

Submission #668129

# Submission time Handle Problem Language Result Execution time Memory
668129 2022-12-02T21:09:45 Z jeroenodb Lampice (COCI19_lampice) C++14
110 / 110
 3006 ms 10388 KB 
#include "bits/stdc++.h"
using namespace std;
#define all(x) begin(x),end(x)
template<typename A, typename B> ostream& operator<<(ostream &os, const pair<A, B> &p) { return os << '(' << p.first << ", " << p.second << ')'; }
template<typename T_container, typename T = typename enable_if<!is_same<T_container, string>::value, typename T_container::value_type>::type> ostream& operator<<(ostream &os, const T_container &v) { string sep; for (const T &x : v) os << sep << x, sep = " "; return os; }
#define debug(a) cerr << "(" << #a << ": " << a << ")\n";
typedef long long ll;
typedef vector<int> vi;
typedef vector<vi> vvi;
typedef pair<int,int> pi;
const int mxN = 5e4+1, oo = 1e9;
const long long MD = 1000001011;
template<long long MOD=MD> struct mdint {
    int d=0;
    mdint () {d=0;}
    mdint (long long _d) : d(_d%MOD){
        if(d<0) d+=MOD;
    };
    friend mdint& operator+=(mdint& a, const mdint& o) {
        a.d+=o.d; if(a.d>=MOD) a.d-=MOD;
        return a;
    }
    friend mdint& operator-=(mdint& a, const mdint& o) {
        a.d-=o.d; if(a.d<0) a.d+=MOD;
        return a;
    }
    friend mdint& operator*=(mdint& a, const mdint& o) {
        return a = mdint((ll)a.d*o.d);
    }
    mdint operator*(const mdint& o) const {
        mdint res = *this;
        res*=o;
        return res;
    }
    mdint operator+(const mdint& o) const {
        mdint res = *this;
        res+=o;
        return res;
    }
    mdint operator-(const mdint& o) const {
        mdint res = *this;
        res-=o;
        return res;
    }
    mdint operator^(long long b) const {
        mdint tmp = 1;
        mdint power = *this;
        while(b) {
            if(b&1) {
                tmp = tmp*power;
            }
            power = power*power;
            b/=2;
        }
        return tmp;
    }
    friend mdint operator/=(mdint& a, const mdint& o) {
        a *= (o^(MOD-2));
        return a;
    }
    mdint operator/(const mdint& o) {
        mdint res = *this;
        res/=o;
        return res;
    }
    bool operator==(const mdint& o) { return d==o.d;}
    bool operator!=(const mdint& o) { return d!=o.d;}
    friend istream& operator>>(istream& c, mdint& a) {return c >> a.d;}
    friend ostream& operator<<(ostream& c, const mdint& a) {return c << a.d;}
};
using  mint = mdint<MD>;
mint pw[mxN];
const mint base = 546575;
void precomp() {
    pw[0]=1;
    for(int i=1;i<mxN;++i) pw[i]=pw[i-1]*base;
}

const int S = 15000019;
struct bloomfilter {
    bitset<S> bs = {};
    vi v;
    bool check(ll i) {
        return bs[i%S] and bs[(i*6755^1244546)%S];
    }
    void clear() {
        for(auto i : v) {
            add(i,0);
        }
        v.clear();
    }
    void add(ll i, bool s=1) {
        if(s) v.push_back(i);
        bs[i%S]=bs[(i*6755^1244546)%S]=s;
    }
} bf[2];

bitset<mxN> vis;
basic_string<int> adj[mxN];
int sz[mxN];
string s;
void dfsz(int at) {
    vis[at]=1;
    sz[at]=1;
    for(int to : adj[at]) if(!vis[to]) {
        dfsz(to);        
        sz[at]+=sz[to];
    }
    vis[at]=0;
}
int LEN;
vector<char> palin = {1};
vector<mint> pref = {0};
int d=1;
bool CHECKING=false;
tuple<bool,bool,int> good() {
    int check = min(d,LEN-d);
    if(d>check) {
        if(!palin[d-check]) return {0,0,0};
    }
    return {true,  d >= (LEN+1 + !CHECKING)/2, (pref.back()- pw[check]*pref[d-check]).d};
}
bool foundLEN=false;
mint b=0;
template<typename F> void dfsD(int at, F func) {
    d++;
    b+=pw[d-1]*s[at];
    pref.push_back(pref.back()*base+s[at]);
    vis[at]=1;
    palin.push_back(pref.back()==b);
    auto [g,big,val] = good();
    if(g) func(val,big);
    for(int to : adj[at]) if(!vis[to]) {
        dfsD(to,func);
    }
    palin.pop_back();
    pref.pop_back();
    vis[at]=0;
    b-=pw[d-1]*s[at];
    d--;
}

int centroid(int at) {
    int total=sz[at], from=-1;
    while(true) {
        bool f=false;
        for(int to : adj[at]) if(to!=from and !vis[to]) {
            if(sz[to]*2>total) {
                from=at;
                at=to;
                f=true;
                break;
            }
        }
        if(!f) return at;
    }
}

bool decomp(int at) {

    dfsz(at);
    int c = centroid(at);
    vis[c]=1;
    for(int to : adj[c]) if(!vis[to]) {
        if(decomp(to)) {
            vis[c]=0;
            return true;
        }
    }
    // now the real work.
    bf[0].add(0);
    for(int to : adj[c]) if(!vis[to]) {
        auto mycheck = [&](int v, bool big) {
            if(bf[!big].check(v)) {
                foundLEN=true;
            }
        };
        auto myadd = [&](int v, bool big) {
            bf[big].add(v);
        };
        d=1;
        palin.push_back(1);
        pref.push_back(s[c]);
        CHECKING=true;
        b=s[c];
        dfsD(to,mycheck);
        palin.pop_back();
        pref.pop_back();
        CHECKING=false;
        d=0;
        b=0;
        dfsD(to,myadd);

        if(foundLEN) break;
    }
    bf[0].clear();
    bf[1].clear();
    vis[c]=0;
    return foundLEN;
}


int main() {
    ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    precomp();
    int n; cin >> n;
    pref.reserve(n+2);
    palin.reserve(n+2);
    for(auto& b : bf) b.v.reserve(n+2);
    cin >> s;
    for(int i=0;i<n-1;++i) {
        int a,b; cin >> a >> b,--a,--b;
        adj[a].push_back(b);
        adj[b].push_back(a);
    }
    int lo = 0,hi=n/2;
    while(lo<hi) {
        int mid = (lo+hi+1)/2;
        LEN = mid*2;
        foundLEN=0;
        if(decomp(0)) {
            lo = mid;
        } else hi = mid-1;
    }
    int ans=lo*2;
    lo=0,hi = (n-1)/2;
    while(lo<hi) {
        int mid = (lo+hi+1)/2;
        LEN = mid*2+1;
        foundLEN=0;
        if(decomp(0)) {
            lo = mid;
        } else hi = mid-1;
    }
    ans = max(ans,lo*2+1);
    cout << ans << '\n';

}

Compilation message

lampice.cpp: In function 'void dfsD(int, F)':
lampice.cpp:131:10: warning: structured bindings only available with '-std=c++17' or '-std=gnu++17'
  131 |     auto [g,big,val] = good();
      |          ^

Subtask #1
17.0 / 17.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5716 KB Output is correct
2 Correct 10 ms 5780 KB Output is correct
3 Correct 25 ms 5796 KB Output is correct
4 Correct 36 ms 5788 KB Output is correct
5 Correct 3 ms 5716 KB Output is correct
6 Correct 3 ms 5716 KB Output is correct
7 Correct 3 ms 5716 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1241 ms 9676 KB Output is correct
2 Correct 1701 ms 9804 KB Output is correct
3 Correct 1670 ms 10012 KB Output is correct
4 Correct 1756 ms 10188 KB Output is correct
5 Correct 1801 ms 10288 KB Output is correct
6 Correct 1996 ms 10388 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 2013 ms 7276 KB Output is correct
2 Correct 2167 ms 7024 KB Output is correct
3 Correct 2113 ms 7356 KB Output is correct
4 Correct 2372 ms 7472 KB Output is correct
5 Correct 2072 ms 7096 KB Output is correct
6 Correct 1343 ms 7048 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 6 ms 5716 KB Output is correct
2 Correct 10 ms 5780 KB Output is correct
3 Correct 25 ms 5796 KB Output is correct
4 Correct 36 ms 5788 KB Output is correct
5 Correct 3 ms 5716 KB Output is correct
6 Correct 3 ms 5716 KB Output is correct
7 Correct 3 ms 5716 KB Output is correct
8 Correct 1241 ms 9676 KB Output is correct
9 Correct 1701 ms 9804 KB Output is correct
10 Correct 1670 ms 10012 KB Output is correct
11 Correct 1756 ms 10188 KB Output is correct
12 Correct 1801 ms 10288 KB Output is correct
13 Correct 1996 ms 10388 KB Output is correct
14 Correct 2013 ms 7276 KB Output is correct
15 Correct 2167 ms 7024 KB Output is correct
16 Correct 2113 ms 7356 KB Output is correct
17 Correct 2372 ms 7472 KB Output is correct
18 Correct 2072 ms 7096 KB Output is correct
19 Correct 1343 ms 7048 KB Output is correct
20 Correct 1209 ms 6452 KB Output is correct
21 Correct 1363 ms 6448 KB Output is correct
22 Correct 2110 ms 6456 KB Output is correct
23 Correct 543 ms 6572 KB Output is correct
24 Correct 2142 ms 7308 KB Output is correct
25 Correct 2160 ms 7020 KB Output is correct
26 Correct 2477 ms 7452 KB Output is correct
27 Correct 2211 ms 6516 KB Output is correct
28 Correct 2167 ms 6572 KB Output is correct
29 Correct 2203 ms 6552 KB Output is correct
30 Correct 3006 ms 7752 KB Output is correct
31 Correct 1813 ms 6968 KB Output is correct
32 Correct 1959 ms 8192 KB Output is correct
33 Correct 1109 ms 7156 KB Output is correct