oj.uz

Submission #321569

# Submission time Handle Problem Language Result Execution time Memory
321569 2020-11-12T18:47:26 Z jc713 Palindromes (APIO14_palindrome) C++17
100 / 100
 61 ms 41704 KB 
#include <ext/pb_ds/tree_policy.hpp>
#include <ext/pb_ds/assoc_container.hpp>
#include <bits/stdc++.h>

using namespace std;
using namespace __gnu_pbds;
template <class T> using Tree = tree<T, null_type, less<T>,
    rb_tree_tag, tree_order_statistics_node_update>;
 
using ll = long long;
using ull = unsigned long long;
using ld = long double;
using db = double; 
using str = string; // yay python!

using pi = pair<int,int>;
using pl = pair<ll,ll>;
using pd = pair<db,db>;

using vi = vector<int>;
using vb = vector<bool>;
using vl = vector<ll>;
using vd = vector<db>; 
using vs = vector<str>;
using vpi = vector<pi>;
using vpl = vector<pl>; 
using vpd = vector<pd>;

#define tcT template<class T
// ^ lol this makes everything look weird but I'll try it
tcT> using V = vector<T>; 
tcT, size_t SZ> using AR = array<T,SZ>; 

// pairs
#define mp make_pair
#define f first
#define s second

// vectors
#define sz(x) (int)(x).size()
#define all(x) begin(x), end(x)
#define rall(x) (x).rbegin(), (x).rend() 
#define sor(x) sort(all(x)) 
#define rsz resize
#define ins insert 
#define ft front() 
#define bk back()
#define pf push_front 
#define pb push_back
#define eb emplace_back 
#define lb lower_bound 
#define ub upper_bound 

// loops
#define FOR(i,a,b) for (int i = (a); i < (b); ++i)
#define F0R(i,a) FOR(i,0,a)
#define ROF(i,a,b) for (int i = (b)-1; i >= (a); --i)
#define R0F(i,a) ROF(i,0,a)
#define trav(a,x) for (auto& a: x)

const int MOD = 1e9+7; // 998244353;
const int MX = 2e5+5;
const ll INF = 1e18; // not too close to LLONG_MAX
const int IINF = 1e9;
const ld PI = acos((ld)-1);
const int xd[4] = {1,0,-1,0}, yd[4] = {0,1,0,-1}; // for every grid problem!!
mt19937 rng((uint32_t)chrono::steady_clock::now().time_since_epoch().count()); 

// helper funcs
constexpr int pct(int x) { return __builtin_popcount(x); } // # of bits set
constexpr int bits(int x) { return 31-__builtin_clz(x); } // floor(log2(x)) 
ll cdiv(ll a, ll b) { return a/b+((a^b)>0&&a%b); } // divide a by b rounded up
ll fdiv(ll a, ll b) { return a/b-((a^b)<0&&a%b); } // divide a by b rounded down

tcT> bool ckmin(T& a, const T& b) {
    return b < a ? a = b, 1 : 0; } // set a = min(a,b)
tcT> bool ckmax(T& a, const T& b) {
    return a < b ? a = b, 1 : 0; }

#define tcTU tcT, class U
tcTU> T fstTrue(T lo, T hi, U f) {
    hi ++; assert(lo <= hi); // assuming f is increasing
    while (lo < hi) { // find first index such that f is true 
        T mid = lo+(hi-lo)/2;
        f(mid) ? hi = mid : lo = mid+1; 
    } 
    return lo;
}
tcTU> T lstTrue(T lo, T hi, U f) {
    lo --; assert(lo <= hi); // assuming f is decreasing
    while (lo < hi) { // find first index such that f is true 
        T mid = lo+(hi-lo+1)/2;
        f(mid) ? lo = mid : hi = mid-1;
    } 
    return lo;
}
tcT> void remDup(vector<T>& v) { // sort and remove duplicates
    sort(all(v)); v.erase(unique(all(v)),end(v)); }
tcTU> void erase(T& t, const U& u) { // don't erase
    auto it = t.find(u); assert(it != end(t));
    t.erase(u); } // element that doesn't exist from (multi)set

// INPUT
#define tcTUU tcT, class ...U
tcT> void re(complex<T>& c);
tcTU> void re(pair<T,U>& p);
tcT> void re(vector<T>& v);
tcT, size_t SZ> void re(AR<T,SZ>& a);

tcT> void re(T& x) { cin >> x; }
void re(db& d) { str t; re(t); d = stod(t); }
void re(ld& d) { str t; re(t); d = stold(t); }
tcTUU> void re(T& t, U&... u) { re(t); re(u...); }

tcT> void re(complex<T>& c) { T a,b; re(a,b); c = {a,b}; }
tcTU> void re(pair<T,U>& p) { re(p.f,p.s); }
tcT> void re(vector<T>& x) { trav(a,x) re(a); }
tcT, size_t SZ> void re(AR<T,SZ>& x) { trav(a,x) re(a); }

// TO_STRING
#define ts to_string
str ts(char c) { return str(1,c); }
str ts(const char* s) { return (str)s; }
str ts(str s) { return s; }
str ts(bool b) { 
    #ifdef LOCAL
        return b ? "true" : "false"; 
    #else 
        return ts((int)b);
    #endif
}
tcT> str ts(complex<T> c) { 
    stringstream ss; ss << c; return ss.str(); }
str ts(vector<bool> v) {
    str res = "{"; F0R(i,sz(v)) res += char('0'+v[i]);
    res += "}"; return res; }
template<size_t SZ> str ts(bitset<SZ> b) {
    str res = ""; F0R(i,SZ) res += char('0'+b[i]);
    return res; }
tcTU> str ts(pair<T,U> p);
tcT> str ts(T v) { // containers with begin(), end()
    #ifdef LOCAL
        bool fst = 1; str res = "{";
        for (const auto& x: v) {
            if (!fst) res += ", ";
            fst = 0; res += ts(x);
        }
        res += "}"; return res;
    #else
        bool fst = 1; str res = "";
        for (const auto& x: v) {
            if (!fst) res += " ";
            fst = 0; res += ts(x);
        }
        return res;

    #endif
}
tcTU> str ts(pair<T,U> p) {
    #ifdef LOCAL
        return "("+ts(p.f)+", "+ts(p.s)+")"; 
    #else
        return ts(p.f)+" "+ts(p.s);
    #endif
}

// OUTPUT
tcT> void pr(T x) { cout << ts(x); }
tcTUU> void pr(const T& t, const U&... u) { 
    pr(t); pr(u...); }
void ps() { pr("\n"); } // print w/ spaces
tcTUU> void ps(const T& t, const U&... u) { 
    pr(t); if (sizeof...(u)) pr(" "); ps(u...); }

// DEBUG
void DBG() { cerr << "]" << endl; }
tcTUU> void DBG(const T& t, const U&... u) {
    cerr << ts(t); if (sizeof...(u)) cerr << ", ";
    DBG(u...); }
#ifdef LOCAL // compile with -DLOCAL, chk -> fake assert
    #define dbg(...) cerr << "Line(" << __LINE__ << ") -> [" << #__VA_ARGS__ << "]: [", DBG(__VA_ARGS__)
    #define chk(...) if (!(__VA_ARGS__)) cerr << "Line(" << __LINE__ << ") -> function(" \
         << __FUNCTION__  << ") -> CHK FAILED: (" << #__VA_ARGS__ << ")" << "\n", exit(0);
#else
    #define dbg(...) 0
    #define chk(...) 0
#endif

// FILE I/O
void setIn(str s) { freopen(s.c_str(),"r",stdin); }
void setOut(str s) { freopen(s.c_str(),"w",stdout); }
void unsyncIO() { cin.tie(0)->sync_with_stdio(0); }
void setIO(str s = "") {
    unsyncIO();
    // cin.exceptions(cin.failbit); 
    // throws exception when do smth illegal
    // ex. try to read letter into int
    if (sz(s)) { setIn(s+".in"), setOut(s+".out"); } // for USACO
}

struct custom_hash {
    static uint64_t splitmix64(uint64_t x) {
        // http://xorshift.di.unimi.it/splitmix64.c
        x += 0x9e3779b97f4a7c15;
        x = (x ^ (x >> 30)) * 0xbf58476d1ce4e5b9;
        x = (x ^ (x >> 27)) * 0x94d049bb133111eb;
        return x ^ (x >> 31);
    }

    size_t operator()(uint64_t x) const {
        static const uint64_t FIXED_RANDOM = chrono::steady_clock::now().time_since_epoch().count();
        return splitmix64(x + FIXED_RANDOM);
    }
};

template<int SZ> struct palTree {
    static const int sigma = 26;
    int s[SZ], len[SZ], link[SZ], to[SZ][sigma];
	ll oc[SZ];
    int n = 0, last = 0, sz;
    palTree() {
		memset(oc, 0, sizeof oc);
		memset(to, 0, sizeof to);
		memset(link, 0, sizeof link);
		memset(len, 0, sizeof len);
		memset(s, 0, sizeof s);
        s[n++] = -1;
        link[0] = 1;
        len[1] = -1;
        sz = 2;
    }
    int get_link(int v) {
        while(s[n-len[v]-2] != s[n-1]) v = link[v];
        return v;
    }
    void add_letter(int c) {
        s[n++] = c;
        last = get_link(last);
        if (!to[last][c]) {
            len[sz] = len[last]+2;
            link[sz] = to[get_link(link[last])][c];
            to[last][c] = sz++;
        }
        last = to[last][c];
        oc[last] ++;
    }
    void prop() {
        vpi v;
        FOR(i,2,sz) v.pb({len[i],i});
        sort(all(v)); reverse(all(v));
        for (auto a: v) oc[link[a.s]] += oc[a.s];
    }
};

int main(){
    setIO();
	string s;
	cin >> s;
	palTree<300010> l;
	F0R(a, sz(s))
		l.add_letter(s[a] - 'a');
	l.prop();
	ll ma = 0;
	FOR(a, 2, l.sz)
		ma = max(ma, (ll)l.len[a] * l.oc[a]);
	cout << ma << endl;
    // you should actually read the stuff at the bottom
}
 
/* stuff you should look for
    * int overflow, array bounds
    * special cases (n=1?)
    * do smth instead of nothing and stay organized
    * WRITE STUFF DOWN
    * DON'T GET STUCK ON ONE APPROACH
*/

Compilation message

palindrome.cpp: In function 'void setIn(str)':
palindrome.cpp:190:28: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  190 | void setIn(str s) { freopen(s.c_str(),"r",stdin); }
      |                     ~~~~~~~^~~~~~~~~~~~~~~~~~~~~
palindrome.cpp: In function 'void setOut(str)':
palindrome.cpp:191:29: warning: ignoring return value of 'FILE* freopen(const char*, const char*, FILE*)', declared with attribute warn_unused_result [-Wunused-result]
  191 | void setOut(str s) { freopen(s.c_str(),"w",stdout); }
      |                      ~~~~~~~^~~~~~~~~~~~~~~~~~~~~~

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 20 ms 36844 KB Output is correct
2 Correct 21 ms 36716 KB Output is correct
3 Correct 20 ms 36716 KB Output is correct
4 Correct 20 ms 36716 KB Output is correct
5 Correct 21 ms 36716 KB Output is correct
6 Correct 20 ms 36716 KB Output is correct
7 Correct 20 ms 36844 KB Output is correct
8 Correct 20 ms 36716 KB Output is correct
9 Correct 20 ms 36716 KB Output is correct
10 Correct 20 ms 36716 KB Output is correct
11 Correct 24 ms 36716 KB Output is correct
12 Correct 20 ms 36716 KB Output is correct
13 Correct 20 ms 36844 KB Output is correct
14 Correct 20 ms 36716 KB Output is correct
15 Correct 20 ms 36716 KB Output is correct
16 Correct 20 ms 36716 KB Output is correct
17 Correct 20 ms 36716 KB Output is correct
18 Correct 21 ms 36736 KB Output is correct
19 Correct 23 ms 36716 KB Output is correct
20 Correct 20 ms 36716 KB Output is correct
21 Correct 21 ms 36716 KB Output is correct
22 Correct 21 ms 36844 KB Output is correct
23 Correct 20 ms 36716 KB Output is correct
24 Correct 21 ms 36716 KB Output is correct
25 Correct 20 ms 36716 KB Output is correct
26 Correct 23 ms 36716 KB Output is correct
27 Correct 21 ms 36716 KB Output is correct
28 Correct 20 ms 36716 KB Output is correct
29 Correct 20 ms 36716 KB Output is correct
30 Correct 21 ms 36716 KB Output is correct
31 Correct 20 ms 36844 KB Output is correct
32 Correct 20 ms 36716 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 36716 KB Output is correct
2 Correct 22 ms 36756 KB Output is correct
3 Correct 20 ms 36716 KB Output is correct
4 Correct 20 ms 36716 KB Output is correct
5 Correct 21 ms 36716 KB Output is correct
6 Correct 20 ms 36716 KB Output is correct
7 Correct 20 ms 36716 KB Output is correct
8 Correct 20 ms 36716 KB Output is correct
9 Correct 20 ms 36716 KB Output is correct
10 Correct 20 ms 36716 KB Output is correct
11 Correct 20 ms 36716 KB Output is correct
12 Correct 21 ms 36716 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 21 ms 36972 KB Output is correct
2 Correct 22 ms 37100 KB Output is correct
3 Correct 21 ms 36972 KB Output is correct
4 Correct 21 ms 36972 KB Output is correct
5 Correct 21 ms 36972 KB Output is correct
6 Correct 22 ms 36972 KB Output is correct
7 Correct 21 ms 36972 KB Output is correct
8 Correct 21 ms 36716 KB Output is correct
9 Correct 21 ms 36716 KB Output is correct
10 Correct 21 ms 36844 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 29 ms 38312 KB Output is correct
2 Correct 35 ms 38184 KB Output is correct
3 Correct 27 ms 38184 KB Output is correct
4 Correct 34 ms 38312 KB Output is correct
5 Correct 32 ms 38184 KB Output is correct
6 Correct 30 ms 38184 KB Output is correct
7 Correct 31 ms 38184 KB Output is correct
8 Correct 22 ms 37100 KB Output is correct
9 Correct 24 ms 37420 KB Output is correct
10 Correct 29 ms 38184 KB Output is correct

Subtask #5
27.0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 47 ms 41600 KB Output is correct
2 Correct 61 ms 41704 KB Output is correct
3 Correct 42 ms 41704 KB Output is correct
4 Correct 60 ms 41704 KB Output is correct
5 Correct 57 ms 41704 KB Output is correct
6 Correct 55 ms 41704 KB Output is correct
7 Correct 53 ms 39808 KB Output is correct
8 Correct 25 ms 37492 KB Output is correct
9 Correct 26 ms 37492 KB Output is correct
10 Correct 50 ms 39660 KB Output is correct
11 Correct 42 ms 41704 KB Output is correct
12 Correct 26 ms 37876 KB Output is correct