oj.uz

Submission #668133

# Submission time Handle Problem Language Result Execution time Memory
668133 2022-12-02T21:25:17 Z jeroenodb Lampice (COCI19_lampice) C++14
110 / 110
 2722 ms 9964 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 = 13000019;
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) {
    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();
    F func;
    if(g) func(val,big);
    for(int to : adj[at]) if(!vis[to]) {
        dfsD<F>(to);
    }
    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]) {
        struct mycheck {
            void operator()(int v, bool big) const {
                if(bf[!big].check(v)) {
                    foundLEN=true;
                }
            }
        };
        struct myadd {
            void operator()(int v, bool big) const {
                bf[big].add(v);
            }
        };
        d=1;
        palin.push_back(1);
        pref.push_back(s[c]);
        CHECKING=true;
        b=s[c];
        dfsD<mycheck>(to);
        palin.pop_back();
        pref.pop_back();
        CHECKING=false;
        d=0;
        b=0;
        dfsD<myadd>(to);

        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);
    }
    for(auto& v : adj) random_shuffle(all(v));
    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)':
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 5 ms 5280 KB Output is correct
2 Correct 10 ms 5204 KB Output is correct
3 Correct 27 ms 5204 KB Output is correct
4 Correct 38 ms 5204 KB Output is correct
5 Correct 3 ms 5204 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5204 KB Output is correct

Subtask #2
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1601 ms 9124 KB Output is correct
2 Correct 2264 ms 9300 KB Output is correct
3 Correct 2156 ms 9548 KB Output is correct
4 Correct 2145 ms 9604 KB Output is correct
5 Correct 2098 ms 9756 KB Output is correct
6 Correct 2438 ms 9964 KB Output is correct

Subtask #3
31.0 / 31.0

# Verdict Execution time Memory Grader output
1 Correct 2053 ms 6788 KB Output is correct
2 Correct 1984 ms 6576 KB Output is correct
3 Correct 2532 ms 6868 KB Output is correct
4 Correct 2722 ms 6980 KB Output is correct
5 Correct 2061 ms 6496 KB Output is correct
6 Correct 1536 ms 6560 KB Output is correct

Subtask #4
37.0 / 37.0

# Verdict Execution time Memory Grader output
1 Correct 5 ms 5280 KB Output is correct
2 Correct 10 ms 5204 KB Output is correct
3 Correct 27 ms 5204 KB Output is correct
4 Correct 38 ms 5204 KB Output is correct
5 Correct 3 ms 5204 KB Output is correct
6 Correct 3 ms 5204 KB Output is correct
7 Correct 3 ms 5204 KB Output is correct
8 Correct 1601 ms 9124 KB Output is correct
9 Correct 2264 ms 9300 KB Output is correct
10 Correct 2156 ms 9548 KB Output is correct
11 Correct 2145 ms 9604 KB Output is correct
12 Correct 2098 ms 9756 KB Output is correct
13 Correct 2438 ms 9964 KB Output is correct
14 Correct 2053 ms 6788 KB Output is correct
15 Correct 1984 ms 6576 KB Output is correct
16 Correct 2532 ms 6868 KB Output is correct
17 Correct 2722 ms 6980 KB Output is correct
18 Correct 2061 ms 6496 KB Output is correct
19 Correct 1536 ms 6560 KB Output is correct
20 Correct 1282 ms 5968 KB Output is correct
21 Correct 1296 ms 5960 KB Output is correct
22 Correct 2033 ms 5968 KB Output is correct
23 Correct 563 ms 6096 KB Output is correct
24 Correct 2198 ms 6752 KB Output is correct
25 Correct 2158 ms 6528 KB Output is correct
26 Correct 2688 ms 6956 KB Output is correct
27 Correct 1897 ms 6024 KB Output is correct
28 Correct 2101 ms 6164 KB Output is correct
29 Correct 2182 ms 6124 KB Output is correct
30 Correct 2667 ms 7256 KB Output is correct
31 Correct 1844 ms 6376 KB Output is correct
32 Correct 1796 ms 7700 KB Output is correct
33 Correct 1051 ms 6592 KB Output is correct