oj.uz

Submission #675669

# Submission time Handle Problem Language Result Execution time Memory
675669 2022-12-27T17:30:48 Z MrBrionix Palindromic Partitions (CEOI17_palindromic) C++17
100 / 100
 5440 ms 99052 KB 
#include<bits/stdc++.h>
using namespace std;

constexpr int MAXN = 1 << 20, LOGN = 21;
int table[LOGN][MAXN];
void build(int N, vector<int> &V) {
    copy(V.begin(), V.begin()+N, table[0]);
    for (int j = 1; j < LOGN; j++) {
        for (int i = 0; i + (1 << j) <= N; i++) {
            table[j][i]=min(table[j-1][i],
                table[j-1][i+(1<<j)/2]);
        }
    }
}
int query(int l, int r) {
    int k = 31 - __builtin_clz(r - l); // [l, r)
    return min(table[k][l], table[k][r-(1 << k)]);
}

template<class T> using V = vector<T>; 
using vi = V<int>;
#define sz(x) int((x).size())
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define each(a,x) for (auto& a: x)
#define all(x) begin(x), end(x)

struct SuffixArray {
    string S; int N; vi sa, isa, lcp;
    void init(string _S) { N = sz(S = _S)+1; genSa(); genLcp(); }
    void genSa() { // sa has size sz(S)+1, starts with sz(S)
        sa = isa = vi(N); sa[0] = N-1; iota(1+all(sa),0);
        sort(1+all(sa),[&](int a, int b) { return S[a] < S[b]; });
        FOR(i,1,N) { int a = sa[i-1], b = sa[i];
            isa[b] = i > 1 && S[a] == S[b] ? isa[a] : i; }
        for (int len = 1; len < N; len *= 2) { // currently sorted
            // by first len chars
            vi s(sa), is(isa), pos(N); iota(all(pos),0); 
            each(t,s) {int T=t-len;if (T>=0) sa[pos[isa[T]]++] = T;}
            FOR(i,1,N) { int a = sa[i-1], b = sa[i]; /// verify that nothing goes out of bounds
                isa[b] = is[a]==is[b]&&is[a+len]==is[b+len]?isa[a]:i; }
        }
    }
    void genLcp() { // Kasai's Algo
        lcp = vi(N-1); int h = 0;
        F0R(b,N-1) { int a = sa[isa[b]-1];
            while (a+h < sz(S) && S[a+h] == S[b+h]) ++h;
            lcp[isa[b]-1] = h; if (h) h--; }
        build(N-1,lcp); /// if we cut off first chars of two strings
        /// with lcp h then remaining portions still have lcp h-1 
    }
    int getLCP(int a, int b) { // lcp of suffixes starting at a,b
       if (a == b) return sz(S)-a;
       int l = isa[a], r = isa[b]; if (l > r) swap(l,r);
       return query(l,r);
    }
};

int invsa[MAXN];
void solve(){
    string s;
    int n;
    cin>>s;
    n=s.size();
    SuffixArray tmp;
    tmp.init(s);
    
    int last=0,ans=0;
    for(int i=0;i<s.size()/2;i++){
        if(s[last]==s[s.size()-1-i] && tmp.getLCP(last,s.size()-1-last-(i-last))>=(i-last+1)){
            last=i+1;
            ans+=2;
        }
    }
    
    if(last!=s.size()/2 || s.size()%2==1)ans++;
    cout<<ans<<"\n";
}

int main(){
    
    ios::sync_with_stdio(false);
    cin.tie(0);
    
    int t;
    cin>>t;
    
    while(t--)solve();
    
    return 0;
}

Compilation message

palindromic.cpp: In function 'void solve()':
palindromic.cpp:69:18: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   69 |     for(int i=0;i<s.size()/2;i++){
      |                 ~^~~~~~~~~~~
palindromic.cpp:76:12: warning: comparison of integer expressions of different signedness: 'int' and 'std::__cxx11::basic_string<char>::size_type' {aka 'long unsigned int'} [-Wsign-compare]
   76 |     if(last!=s.size()/2 || s.size()%2==1)ans++;
      |        ~~~~^~~~~~~~~~~~
palindromic.cpp:62:9: warning: variable 'n' set but not used [-Wunused-but-set-variable]
   62 |     int n;
      |         ^

Subtask #1
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 340 KB Output is correct

Subtask #2
20.0 / 20.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct

Subtask #3
25.0 / 25.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 20 ms 1252 KB Output is correct
11 Correct 12 ms 1192 KB Output is correct
12 Correct 19 ms 1252 KB Output is correct
13 Correct 17 ms 1100 KB Output is correct

Subtask #4
40.0 / 40.0

# Verdict Execution time Memory Grader output
1 Correct 1 ms 340 KB Output is correct
2 Correct 1 ms 340 KB Output is correct
3 Correct 0 ms 340 KB Output is correct
4 Correct 1 ms 332 KB Output is correct
5 Correct 1 ms 340 KB Output is correct
6 Correct 1 ms 340 KB Output is correct
7 Correct 1 ms 340 KB Output is correct
8 Correct 1 ms 340 KB Output is correct
9 Correct 1 ms 340 KB Output is correct
10 Correct 20 ms 1252 KB Output is correct
11 Correct 12 ms 1192 KB Output is correct
12 Correct 19 ms 1252 KB Output is correct
13 Correct 17 ms 1100 KB Output is correct
14 Correct 4182 ms 99052 KB Output is correct
15 Correct 3229 ms 97740 KB Output is correct
16 Correct 5440 ms 96804 KB Output is correct
17 Correct 3510 ms 50524 KB Output is correct