oj.uz

Submission #668125

# Submission time Handle Problem Language Result Execution time Memory
668125 2022-12-02T21:03:37 Z jeroenodb Lampice (COCI19_lampice) C++14
110 / 110
 2755 ms 11612 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 = 20000019;
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 7 ms 6868 KB Output is correct
2 Correct 10 ms 6996 KB Output is correct
3 Correct 25 ms 7012 KB Output is correct
4 Correct 37 ms 7020 KB Output is correct
5 Correct 3 ms 6868 KB Output is correct
6 Correct 3 ms 6868 KB Output is correct
7 Correct 3 ms 6872 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1451 ms 10836 KB Output is correct
2 Correct 1951 ms 10932 KB Output is correct
3 Correct 2182 ms 11124 KB Output is correct
4 Correct 2688 ms 11316 KB Output is correct
5 Correct 2552 ms 11464 KB Output is correct
6 Correct 2424 ms 11612 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 2339 ms 8492 KB Output is correct
2 Correct 2755 ms 8276 KB Output is correct
3 Correct 2485 ms 8588 KB Output is correct
4 Correct 2600 ms 8620 KB Output is correct
5 Correct 2555 ms 8212 KB Output is correct
6 Correct 1634 ms 8268 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 7 ms 6868 KB Output is correct
2 Correct 10 ms 6996 KB Output is correct
3 Correct 25 ms 7012 KB Output is correct
4 Correct 37 ms 7020 KB Output is correct
5 Correct 3 ms 6868 KB Output is correct
6 Correct 3 ms 6868 KB Output is correct
7 Correct 3 ms 6872 KB Output is correct
8 Correct 1451 ms 10836 KB Output is correct
9 Correct 1951 ms 10932 KB Output is correct
10 Correct 2182 ms 11124 KB Output is correct
11 Correct 2688 ms 11316 KB Output is correct
12 Correct 2552 ms 11464 KB Output is correct
13 Correct 2424 ms 11612 KB Output is correct
14 Correct 2339 ms 8492 KB Output is correct
15 Correct 2755 ms 8276 KB Output is correct
16 Correct 2485 ms 8588 KB Output is correct
17 Correct 2600 ms 8620 KB Output is correct
18 Correct 2555 ms 8212 KB Output is correct
19 Correct 1634 ms 8268 KB Output is correct
20 Correct 1535 ms 7752 KB Output is correct
21 Correct 1461 ms 7688 KB Output is correct
22 Correct 2211 ms 7672 KB Output is correct
23 Correct 565 ms 7940 KB Output is correct
24 Correct 2315 ms 8452 KB Output is correct
25 Correct 2282 ms 8244 KB Output is correct
26 Correct 2659 ms 8680 KB Output is correct
27 Correct 2191 ms 7740 KB Output is correct
28 Correct 2115 ms 7784 KB Output is correct
29 Correct 2160 ms 7780 KB Output is correct
30 Correct 2752 ms 8972 KB Output is correct
31 Correct 1828 ms 8088 KB Output is correct
32 Correct 1970 ms 9572 KB Output is correct
33 Correct 1242 ms 8304 KB Output is correct