Submission #229659

#	Time	Username	Problem	Language	Result	Execution time	Memory
229659		tatyam	Palindromes (APIO14_palindrome)	C++17	100 / 100	654 ms	53280 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
using ll = long long;
using ld = long double;
using ull = unsigned long long;
using uint = unsigned int;
using pcc = pair<char, char>;
using pii = pair<int, int>;
using pll = pair<ll, ll>;
using pdd = pair<double, double>;
using tuplis = array<ll, 3>;
template<class T> using pq = priority_queue<T, vector<T>, greater<T>>;
const ll LINF=0x1fffffffffffffff;
const ll MINF=0x7fffffffffff;
const int INF=0x3fffffff;
const int MOD=1000000007;
const int MODD=998244353;
const ld DINF=numeric_limits<ld>::infinity();
const ld EPS=1e-9;
const ld PI=3.1415926535897932;
const ll dx[] = {0, 1, 0, -1, 1, 1, -1, -1};
const ll dy[] = {1, 0, -1, 0, 1, -1, 1, -1};
#define overload4(_1,_2,_3,_4,name,...) name
#define overload3(_1,_2,_3,name,...) name
#define rep1(n) for(ll i=0;i<n;++i)
#define rep2(i,n) for(ll i=0;i<n;++i)
#define rep3(i,a,b) for(ll i=a;i<b;++i)
#define rep4(i,a,b,c) for(ll i=a;i<b;i+=c)
#define rep(...) overload4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
#define rrep1(n) for(ll i=(n);i--;)
#define rrep2(i,n) for(ll i=(n);i--;)
#define rrep3(i,a,b) for(ll i=(b);i-->(a);)
#define rrep4(i,a,b,c) for(ll i=a+(b-a-1)/c*c;i>=a;i-=c)
#define rrep(...) overload4(__VA_ARGS__,rrep4,rrep3,rrep2,rrep1)(__VA_ARGS__)
#define each(i,a) for(auto&& i:a)
#define all1(i) begin(i),end(i)
#define all2(i,a) begin(i),begin(i)+a
#define all3(i,a,b) begin(i)+a,begin(i)+b
#define all(...) overload3(__VA_ARGS__,all3,all2,all1)(__VA_ARGS__)
#define rall1(i) (i).rbegin(),(i).rend()
#define rall2(i,k) (i).rbegin(),(i).rbegin()+k
#define rall3(i,a,b) (i).rbegin()+a,(i).rbegin()+b
#define rall(...) overload3(__VA_ARGS__,rall3,rall2,rall1)(__VA_ARGS__)
#define sum(...) accumulate(all(__VA_ARGS__),0LL)
#define dsum(...) accumulate(all(__VA_ARGS__),0.0L)
#define elif else if
#define unless(a) if(!(a))
#define mp make_pair
#define mt make_tuple
#define INT(...) int __VA_ARGS__;in(__VA_ARGS__)
#define LL(...) ll __VA_ARGS__;in(__VA_ARGS__)
#define ULL(...) ull __VA_ARGS__;in(__VA_ARGS__)
#define STR(...) string __VA_ARGS__;in(__VA_ARGS__)
#define CHR(...) char __VA_ARGS__;in(__VA_ARGS__)
#define DBL(...) double __VA_ARGS__;in(__VA_ARGS__)
#define LD(...) ld __VA_ARGS__;in(__VA_ARGS__)
#define Sort(a) sort(all(a))
#define Rev(a) reverse(all(a))
#define Uniq(a) sort(all(a));a.erase(unique(all(a)),end(a))
#define vec(type,name,...) vector<type> name(__VA_ARGS__)
#define VEC(type,name,size) vector<type> name(size);in(name)
#define vv(type,name,h,...) vector<vector<type>>name(h,vector<type>(__VA_ARGS__))
#define VV(type,name,h,w) vector<vector<type>>name(h,vector<type>(w));in(name)
#define vvv(type,name,h,w,...) vector<vector<vector<type>>>name(h,vector<vector<type>>(w,vector<type>(__VA_ARGS__)))
template<class T> auto min(const T& a){ return *min_element(all(a)); }
template<class T> auto max(const T& a){ return *max_element(all(a)); }
inline ll popcnt(ull a){ return __builtin_popcountll(a); }
ll gcd(ll a, ll b){ while(b){ ll c = b; b = a % b; a = c; } return a; }
ll lcm(ll a, ll b){ if(!a || !b) return 0; return a * b / gcd(a, b); }
ll intpow(ll a, ll b){ ll ans = 1; while(b){ if(b & 1) ans *= a; a *= a; b /= 2; } return ans; }
ll modpow(ll a, ll b, ll p){ ll ans = 1; while(b){ if(b & 1) (ans *= a) %= p; (a *= a) %= p; b /= 2; } return ans; }
template<class T, class U> bool chmin(T& a, const U& b){ if(a > b){ a = b; return 1; } return 0; }
template<class T, class U> bool chmax(T& a, const U& b){ if(a < b){ a = b; return 1; } return 0; }
vector<ll> iota(ll n){ vector<ll> a(n); iota(a.begin(), a.end(), 0); return a; }
vector<pll> factor(ull x){ vector<pll> ans; for(ll i = 2; i * i <= x; i++) if(x % i == 0){ ans.push_back({i, 1}); while((x /= i) % i == 0) ans.back().second++; } if(x != 1) ans.push_back({x, 1}); return ans; }
map<ll,ll> factor_map(ull x){ map<ll,ll> ans; for(ll i = 2; i * i <= x; i++) if(x % i == 0){ ans[i] = 1; while((x /= i) % i == 0) ans[i]++; } if(x != 1) ans[x] = 1; return ans; }
vector<uint> divisor(uint x){ vector<uint> ans; for(uint i = 1; i * i <= x; i++) if(x % i == 0) ans.push_back(i); rrep(ans.size() - (ans.back() * ans.back() == x)) ans.push_back(x / ans[i]); return ans; }
template<class T> unordered_map<T, ll> press(vector<T>& a){ auto b = a; sort(all(b)); b.erase(unique(all(b)), b.end()); unordered_map<T, ll> ans; rep(b.size()) ans[b[i]] = i; each(i, a) i = ans[i]; return ans; }
template<class T> map<T, ll> press_map(vector<T>& a){ auto b = a; sort(all(b)); b.erase(unique(all(b)), b.end()); map<T, ll> ans; rep(b.size()) ans[b[i]] = i; each(i, a) i = ans[i]; return ans; }
int scan(){ return getchar(); }
void scan(int& a){ scanf("%d", &a); }
void scan(unsigned& a){ scanf("%u", &a); }
void scan(long& a){ scanf("%ld", &a); }
void scan(long long& a){ scanf("%lld", &a); }
void scan(unsigned long long& a){ scanf("%llu", &a); }
void scan(char& a){ do{ a = getchar(); }while(a == ' ' || a == '\n'); }
void scan(float& a){ scanf("%f", &a); }
void scan(double& a){ scanf("%lf", &a); }
void scan(long double& a){ scanf("%Lf", &a); }
void scan(vector<bool>& a){ for(unsigned i = 0; i < a.size(); i++){ int b; scan(b); a[i] = b; } }
void scan(char a[]){ scanf("%s", a); }
void scan(string& a){ cin >> a; }
template<class T> void scan(vector<T>&);
template<class T, size_t size> void scan(array<T, size>&);
template<class T, class L> void scan(pair<T, L>&);
template<class T, size_t size> void scan(T(&)[size]);
template<class T> void scan(vector<T>& a){ for(auto&& i : a) scan(i); }
template<class T> void scan(deque<T>& a){ for(auto&& i : a) scan(i); }
template<class T, size_t size> void scan(array<T, size>& a){ for(auto&& i : a) scan(i); }
template<class T, class L> void scan(pair<T, L>& p){ scan(p.first); scan(p.second); }
template<class T, size_t size> void scan(T (&a)[size]){ for(auto&& i : a) scan(i); }
template<class T> void scan(T& a){ cin >> a; }
void in(){}
template <class Head, class... Tail> void in(Head& head, Tail&... tail){ scan(head); in(tail...); }
void print(){ putchar(' '); }
void print(bool a){ printf("%d", a); }
void print(int a){ printf("%d", a); }
void print(unsigned a){ printf("%u", a); }
void print(long a){ printf("%ld", a); }
void print(long long a){ printf("%lld", a); }
void print(unsigned long long a){ printf("%llu", a); }
void print(char a){ printf("%c", a); }
void print(char a[]){ printf("%s", a); }
void print(const char a[]){ printf("%s", a); }
void print(float a){ printf("%.15f", a); }
void print(double a){ printf("%.15f", a); }
void print(long double a){ printf("%.15Lf", a); }
void print(const string& a){ for(auto&& i : a) print(i); }
template<class T> void print(const vector<T>&);
template<class T, size_t size> void print(const array<T, size>&);
template<class T, class L> void print(const pair<T, L>& p);
template<class T, size_t size> void print(const T (&)[size]);
template<class T> void print(const vector<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T> void print(const deque<T>& a){ if(a.empty()) return; print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T, size_t size> void print(const array<T, size>& a){ print(a[0]); for(auto i = a.begin(); ++i != a.end(); ){ putchar(' '); print(*i); } }
template<class T, class L> void print(const pair<T, L>& p){ print(p.first); putchar(' '); print(p.second); }
template<class T, size_t size> void print(const T (&a)[size]){ print(a[0]); for(auto i = a; ++i != end(a); ){ putchar(' '); print(*i); } }
template<class T> void print(const T& a){ cout << a; }
int out(){ putchar('\n'); return 0; }
template<class T> int out(const T& t){ print(t); putchar('\n'); return 0; }
template<class Head, class... Tail> int out(const Head& head, const Tail&... tail){ print(head); putchar(' '); out(tail...); return 0; }
#ifdef DEBUG
inline int __lg(int __n){ return sizeof(int) * __CHAR_BIT__  - 1 - __builtin_clz(__n); }
#define debug(...) { print(#__VA_ARGS__); print(":"); out(__VA_ARGS__); }
#else
#define debug(...) void(0)
#endif
int first(bool i = true){ return out(i?"first":"second"); }
int yes(bool i = true){ return out(i?"yes":"no"); }
int Yes(bool i = true){ return out(i?"Yes":"No"); }
int No(){ return out("No"); }
int YES(bool i = true){ return out(i?"YES":"NO"); }
int NO(){ return out("NO"); }
int Yay(bool i = true){ return out(i?"Yay!":":("); }
int possible(bool i = true){ return out(i?"possible":"impossible"); }
int Possible(bool i = true){ return out(i?"Possible":"Impossible"); }
int POSSIBLE(bool i = true){ return out(i?"POSSIBLE":"IMPOSSIBLE"); }
void Case(ll i){ printf("Case #%lld: ", i); }


vector< int > manacher(const string &s) {
  vector< int > radius(s.size());
  int i = 0, j = 0;
  while(i < s.size()) {
    while(i - j >= 0 && i + j < s.size() && s[i - j] == s[i + j]) {
      ++j;
    }
    radius[i] = j;
    int k = 1;
    while(i - k >= 0 && i + k < s.size() && k + radius[i - k] < j) {
      radius[i + k] = radius[i - k];
      ++k;
    }
    i += k;
    j -= k;
  }
  return radius;
}
const unsigned bases[64] = {257,262,266,275,276,281,285,290,296,302,306,310,311,313,323,333,344,345,350,357,367,370,373,402,423,425,431,440,442,443,454,457,458,462,471,478,481,487,489,492,499,501,502,503,506,514,524,532,535,541,550,552,557,559,562,563,567,570,571,580,592,597,604,612};
const ull mod = 0x1fffffffffffffff, base = bases[chrono::duration_cast<chrono::microseconds>(chrono::system_clock::now().time_since_epoch()).count() & 63];
struct RollingHash {
    vector<ull> hashed, power;
    
    static constexpr ull mask(int a) { return (1ull << a) - 1; }
    
    inline ull mul(ull a, ull b) const {
        //*
        __uint128_t ans = __uint128_t(a) * b;
        /*/
         // without __uint128_t
         ull a31 = a >> 31, b31 = b >> 31;
         a &= mask(31);
         b &= mask(31);
         ull x = a * b31 + b * a31;
         ull ans = (a31 * b31 << 1) + (x >> 30) + ((x & mask(30)) << 31) + a * b;
         //*/
        ans = (ans >> 61) + (ans & mask(61));
        if(ans >= mod) ans -= mod;
        return ans;
    }
    
    
    RollingHash(const string &s) {
        ll n = s.size();
        hashed.assign(n + 1, 0);
        power.assign(n + 1, 0);
        power[0] = 1;
        rep(n) {
            power[i + 1] = mul(power[i], base);
            hashed[i + 1] = mul(hashed[i], base) + s[i];
            if(hashed[i + 1] >= mod) hashed[i + 1] -= mod;
        }
    }
    
    ull get(ll l, ll r) const {
        ull ret = hashed[r] + mod - mul(hashed[l], power[r - l]);
        if(ret >= mod) ret -= mod;
        return ret;
    }
    
    ull connect(ull h1, ull h2, ll h2len) const {
        ull ret = mul(h1, power[h2len]) + h2;
        if(ret >= mod) ret -= mod;
        return ret;
    }
    
    void connect(const string &s){
        ll n = hashed.size() - 1, m = s.size();
        hashed.resize(n + m + 1);
        power.resize(n + m + 1);
        rep(i, n, n + m) {
            power[i + 1] = mul(power[i], base);
            hashed[i + 1] = mul(hashed[i], base) + s[i - n];
            if(hashed[i + 1] >= mod) hashed[i + 1] -= mod;
        }
    }
    
    ll LCP(const RollingHash &b, ll l1, ll r1, ll l2, ll r2) {
        ll len = min(r1 - l1, r2 - l2);
        ll low = -1, high = len + 1;
        while(high - low > 1) {
            ll mid = (low + high) / 2;
            if(get(l1, l1 + mid) == b.get(l2, l2 + mid)) low = mid;
            else high = mid;
        }
        return low;
    }
};
signed main(){
    STR(s);
    string t={s[0]};
    ll n=s.size();
    rep(i,1,n){
        t+='$';
        t+=s[i];
    }
    auto mn=manacher(t);
    ll ans=0;
    RollingHash rh(s);
    vector<pll>a;
    unordered_map<ull,ll>cnt;
    rep(t.size())a.push_back({(i-mn[i]+2)/2,(i+mn[i]+1)/2});
    auto comp=[](pll a,pll b){return a.second-a.first<b.second-b.first;};
    priority_queue<pll,vector<pll>,decltype(comp)>q(comp);
    unordered_set<ull>used;
    each(i,a){
        q.push(i);
        cnt[rh.get(i.first,i.second)]++;
    }
    while(q.size()){
        auto [l,r]=q.top();
        q.pop();
        if(l>=r)continue;
        ll hash=rh.get(l,r);
        if(used.count(hash))continue;
        used.insert(hash);
        chmax(ans,cnt[hash]*(r-l));
        if(r-l>2){
            l++;
            r--;
            cnt[rh.get(l,r)]+=cnt[hash];
            q.emplace(l,r);
        }
    }
    out(ans);
}

Compilation message (stderr)

palindrome.cpp: In function 'std::vector<int> manacher(const string&)':
palindrome.cpp:154:11: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
   while(i < s.size()) {
         ~~^~~~~~~~~~
palindrome.cpp:155:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(i - j >= 0 && i + j < s.size() && s[i - j] == s[i + j]) {
                         ~~~~~~^~~~~~~~~~
palindrome.cpp:160:31: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     while(i - k >= 0 && i + k < s.size() && k + radius[i - k] < j) {
                         ~~~~~~^~~~~~~~~~
palindrome.cpp: In function 'int main()':
palindrome.cpp:25:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
 #define rep1(n) for(ll i=0;i<n;++i)
                             ^
palindrome.cpp:23:41: note: in expansion of macro 'rep1'
 #define overload4(_1,_2,_3,_4,name,...) name
                                         ^~~~
palindrome.cpp:29:18: note: in expansion of macro 'overload4'
 #define rep(...) overload4(__VA_ARGS__,rep4,rep3,rep2,rep1)(__VA_ARGS__)
                  ^~~~~~~~~
palindrome.cpp:252:5: note: in expansion of macro 'rep'
     rep(t.size())a.push_back({(i-mn[i]+2)/2,(i+mn[i]+1)/2});
     ^~~
palindrome.cpp: In function 'void scan(int&)':
palindrome.cpp:81:25: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(int& a){ scanf("%d", &a); }
                    ~~~~~^~~~~~~~~~
palindrome.cpp: In function 'void scan(unsigned int&)':
palindrome.cpp:82:30: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(unsigned& a){ scanf("%u", &a); }
                         ~~~~~^~~~~~~~~~
palindrome.cpp: In function 'void scan(long int&)':
palindrome.cpp:83:26: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(long& a){ scanf("%ld", &a); }
                     ~~~~~^~~~~~~~~~~
palindrome.cpp: In function 'void scan(long long int&)':
palindrome.cpp:84:31: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(long long& a){ scanf("%lld", &a); }
                          ~~~~~^~~~~~~~~~~~
palindrome.cpp: In function 'void scan(long long unsigned int&)':
palindrome.cpp:85:40: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(unsigned long long& a){ scanf("%llu", &a); }
                                   ~~~~~^~~~~~~~~~~~
palindrome.cpp: In function 'void scan(float&)':
palindrome.cpp:87:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(float& a){ scanf("%f", &a); }
                      ~~~~~^~~~~~~~~~
palindrome.cpp: In function 'void scan(double&)':
palindrome.cpp:88:28: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(double& a){ scanf("%lf", &a); }
                       ~~~~~^~~~~~~~~~~
palindrome.cpp: In function 'void scan(long double&)':
palindrome.cpp:89:33: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(long double& a){ scanf("%Lf", &a); }
                            ~~~~~^~~~~~~~~~~
palindrome.cpp: In function 'void scan(char*)':
palindrome.cpp:91:27: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
 void scan(char a[]){ scanf("%s", a); }
                      ~~~~~^~~~~~~~~

• Subtask 1: 8 / 8
• Subtask 2: 15 / 15
• Subtask 3: 24 / 24
• Subtask 4: 26 / 26
• Subtask 5: 27 / 27