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Submission #259056

# Submission time Handle Problem Language Result Execution time Memory
259056 2020-08-07T06:02:50 Z pure_mem Palindromes (APIO14_palindrome) C++14
73 / 100
 1000 ms 65556 KB 
#include <bits/stdc++.h>
 
#define ll long long
#define X first
#define Y second
#define MP make_pair
 
using namespace std;
 
const int N = 3e5 + 3;
 
struct sarr{
	ll mod1 = 1e9 + 7, mod2 = 1e9 + 9, mod3 = 1e9 + 21;
	ll pr1[N], pr2[N], pr3[N];
	ll hs1[N], hs2[N], hs3[N], rhs1[N], rhs2[N], rhs3[N];
	int sf[N], poses[N], lcm[N], sp[19][N], lg[N];
	string s;
 
	map< pair< pair< int, int >, int >, bool > were;
 
	void init(string temp){
		s = temp;
		pr1[0] = pr2[0] = pr3[0] = 1;
		lg[1] = 0;
		for(int i = 1;i < N;i++){
			pr1[i] = pr1[i - 1] * 29 % mod1;
			pr2[i] = pr2[i - 1] * 31 % mod2;
			pr3[i] = pr3[i - 1] * 37 % mod3;
			if(i > 1)
				lg[i] = lg[i / 2] + 1;
		}
		for(int i = 0;i < (int)temp.size();i++){
			sf[i + 1] = i + 1;
			hs1[i + 1] = (hs1[i] + (temp[i] - 'a' + 1) * pr1[i]) % mod1;
			hs2[i + 1] = (hs2[i] + (temp[i] - 'a' + 1) * pr2[i]) % mod2;
			hs3[i + 1] = (hs3[i] + (temp[i] - 'a' + 1) * pr3[i]) % mod3;	
		}
		for(int i = 0;i < (int)temp.size();i++){
			int j = (int)temp.size() - i - 1;
			rhs1[j + 1] = (rhs1[j + 2] + (temp[j] - 'a' + 1) * pr1[i]) % mod1;
			rhs2[j + 1] = (rhs2[j + 2] + (temp[j] - 'a' + 1) * pr2[i]) % mod2;
			rhs3[j + 1] = (rhs3[j + 2] + (temp[j] - 'a' + 1) * pr3[i]) % mod3;	
		}
		this->build_sf();
		for(int i = 1;i < (int)temp.size();i++){
			lcm[i] = this->get_lcm(sf[i], sf[i + 1]);
		//	cerr << lcm[i] << " ";
		}
		//cerr << endl;
		for(int i = 1;i <= (int)temp.size();i++){
			sp[0][i] = lcm[i];
		//	cerr << sf[i] << " ";
			poses[sf[i]] = i;
		}
		for(int i = 1;i < 19;i++){
			for(int j = 1;j + (1 << i) - 1 <= (int)temp.size();j++){
				sp[i][j] = min(sp[i - 1][j], sp[i - 1][j + (1 << (i - 1))]);
			}
		}
	}

	void build_sf(){
		string temp = s;
		temp += "#"; 
		int n = temp.size();
		vector<int> cl(n, 0), pn(n, 0), cn(n, 0), p(n, 0), cnt(n, 0);
		for(int i = 0;i < n;i++)
			p[i] = i;
		sort(p.begin(), p.end(), [this](int x, int y){
			if(s[x] < s[y])
				return 1;
			return 0;
		});
		int classes = 0;
		for(int i = 1;i < n;i++){
			if(s[p[i]] != s[p[i - 1]])
				classes++;
			cl[p[i]] = classes;
		}
		for(int it = 0;(1 << it) < n;it++){
			for(int i = 0;i < n;i++){
				pn[i] = p[i] - (1 << it);
				if(pn[i] < 0)
					pn[i] += n;
			}
			cnt.assign(cnt.size(), 0);
			for(int i = 0;i < n;i++){
				++cnt[cl[pn[i]]];
			}
			for(int i = 1;i <= classes;i++){
				cnt[i] += cnt[i - 1];	
			}
			for(int i = n - 1;i >= 0;i--){
				p[--cnt[cl[pn[i]]]] = pn[i];
			}
			cn[p[0]] = 0;
			classes = 0;
			for(int i = 1;i < n;i++){
				int m1 = (p[i] + (1 << it)) % n, m2 = (p[i - 1] + (1 << it)) % n;
				if(cl[p[i]] != cl[p[i - 1]] || cl[m1] != cl[m2])
					classes++;
				cn[p[i]] = classes;
			}
			for(int i = 0;i < n;i++)
				cl[i] = cn[i];
		}
		for(int i = 2;i <= n;i++){
			sf[i - 1] = p[i - 1] + 1;	
		}
	}
 
	bool check(int l, int r){
		bool can = 1;
		ll add1 = 0, add2 = 0;
		if(l > (int)s.size() - r + 1)
			add2 = l - ((int)s.size() - r + 1);
		else
			add1 = (int)s.size() - r + 1 - l;
		if((hs1[r] - hs1[l - 1] + mod1) % mod1 * pr1[add1] % mod1 != (rhs1[l] - rhs1[r + 1] + mod1) % mod1 * pr1[add2] % mod1)
			can = 0;
		if((hs2[r] - hs2[l - 1] + mod2) % mod2 * pr2[add1] % mod2 != (rhs2[l] - rhs2[r + 1] + mod2) % mod2 * pr2[add2] % mod2)
			can = 0;
		if((hs3[r] - hs3[l - 1] + mod3) % mod3 * pr3[add1] % mod3 != (rhs3[l] - rhs3[r + 1] + mod3) % mod3 * pr3[add2] % mod3)
			can = 0;
		return can;
	}
 
	bool check_eq(int l1, int r1, int l2, int r2){
		bool can = 1;
		if(l1 > l2)
			swap(l1, l2), swap(r1, r2);
		if(((hs1[r1] - hs1[l1 - 1] + mod1) % mod1) * pr1[l2 - l1] % mod1 != (hs1[r2] - hs1[l2 - 1] + mod1) % mod1)
			can = 0;
		if(((hs2[r1] - hs2[l1 - 1] + mod2) % mod2) * pr2[l2 - l1] % mod2 != (hs2[r2] - hs2[l2 - 1] + mod2) % mod2)
			can = 0;
		if(((hs3[r1] - hs3[l1 - 1] + mod3) % mod3) * pr3[l2 - l1] % mod3 != (hs3[r2] - hs3[l2 - 1] + mod3) % mod3)
			can = 0;
		return can;
	}
 
	int get_lcm(int l, int r){
		if(l > r)
			swap(l, r);
		int tl = 1, tr = (int)s.size() - r + 1, tp = 0;
		while(tl <= tr){
			int tm = (tl + tr) / 2;
			if(this->check_eq(l, l + tm - 1, r, r + tm - 1))
				tl = tm + 1, tp = tm;
			else
				tr = tm - 1;
		}
		return tp;
	}
 
	bool is_less(int l, int r){
		int lc = this->get_lcm(l, r);
		if(l + lc - 1 == (int)s.size())
			return 1;
		else if(r + lc - 1 == (int)s.size())
			return 0;
		return s[l + lc - 1] < s[r + lc - 1];
	}
 
	bool is_were(int l, int r){
		ll hash1 = ((hs1[r] - hs1[l - 1] + mod1) % mod1) * pr1[(int)s.size() - l] % mod1;
		ll hash2 = ((hs2[r] - hs2[l - 1] + mod2) % mod2) * pr2[(int)s.size() - l] % mod2;
		ll hash3 = ((hs3[r] - hs3[l - 1] + mod3) % mod3) * pr3[(int)s.size() - l] % mod3;
		//cerr << hash1 << " " << l << " " << r << "\n";
		if(were.count(MP(MP(hash1, hash2), hash3)))
			return 0;
		were[MP(MP(hash1, hash2), hash3)] = 1;
		return 1;
	}
 
	int lcm_min(int l, int r){
		if(l == r)
			return (int)s.size() - l + 1;
		r -= 1;
		int lens = (r - l + 1);
		//cerr << lg[lens] << " " << lens << " " << sp[lg[lens]][l] << "s\n";
		return min(sp[lg[lens]][l], sp[lg[lens]][r - (1 << lg[lens]) + 1]);	
	}
 
	int get_cnt(int l, int r){
		int idx = poses[l];
		int tl = 1, tr = idx - 1, res = 1;
		while(tl <= tr){
			int tm = (tl + tr) / 2;
			if(this->lcm_min(tm, idx) >= r - l + 1){
				tr = tm - 1, res = idx - tm + 1;
			}
			else{
				tl = tm + 1;
			}
		}
		int tp = 1;
		tl = idx + 1, tr = (int)s.size();
		while(tl <= tr){
			int tm = (tl + tr) / 2;
			if(this->lcm_min(idx, tm) >= r - l + 1){
				tl = tm + 1, tp = tm - idx + 1;
			}
			else{
				tr = tm - 1;
			}
		}
	//	cerr << res << " " << tp << "\n";
		return res + tp - 1;
	}
}g;
 
int main () {
	ios::sync_with_stdio(0);
	cin.tie(0);
	cout.tie(0);
 
    cin >> g.s;
    //cerr << g.s << "\n";
    ll res = 0;
    g.init(g.s);
    int n = g.s.size();
   // cerr << g.check(26, 27) << " " << g.s[25] << " " << g.s[26]<< "\n";
    for(int mid = 1;mid <= n;mid++){
    	int tr = min(mid - 1, n - mid), tl = 1, tp = 0;
    	while(tl <= tr){
    		int tm = (tl + tr) / 2;
    		if(g.check(mid - tm, mid + tm))
    			tl = tm + 1, tp = tm;
    		else
    			tr = tm - 1;
    	}
    //	cerr << mid << " " << tp << "\n";
    	for(int l = mid - tp, r = mid + tp; l <= r;l++, r--){
    	//	cerr << "was " << " " << l << " " << r << "\n";
    		if(!g.is_were(l, r))
    			break;
    		//break; // UBRAT ------------------------------------------------
    	//	cerr << "was\n";
    	//	cerr << l << " " << r << " " << g.get_cnt(l, r) << "\n";
    		res = max(res, (r - l + 1ll) * g.get_cnt(l, r));
    	}
    }
    //cerr << g.get_cnt(5, 6) << "\n";
    for(int mid = 2;mid <= n;mid++){
    	if(g.s[mid - 1] != g.s[mid - 2])
    		continue;
    	int tr = min(mid - 2, n - mid), tl = 1, tp = 0;
    	while(tl <= tr){
    		int tm = (tl + tr) / 2;
    		if(g.check(mid - 1 - tm, mid + tm))
    			tl = tm + 1, tp = tm;
    		else
    			tr = tm - 1;
    	}
    	for(int l = mid - 1 - tp, r = mid + tp; l <= r;l++, r--){
    		if(!g.is_were(l, r))
    			break;
    	//	cerr << l << " " << r << " " << g.get_cnt(l, r) << "\n";
    		res = max(res, (r - l + 1ll) * g.get_cnt(l, r));
    	}
    }
    cout << res;
}

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 9 ms 8576 KB Output is correct
2 Correct 9 ms 8576 KB Output is correct
3 Correct 9 ms 8704 KB Output is correct
4 Correct 9 ms 8576 KB Output is correct
5 Correct 10 ms 8576 KB Output is correct
6 Correct 9 ms 8704 KB Output is correct
7 Correct 9 ms 8576 KB Output is correct
8 Correct 9 ms 8704 KB Output is correct
9 Correct 10 ms 8704 KB Output is correct
10 Correct 10 ms 8704 KB Output is correct
11 Correct 10 ms 8704 KB Output is correct
12 Correct 9 ms 8704 KB Output is correct
13 Correct 9 ms 8704 KB Output is correct
14 Correct 10 ms 8704 KB Output is correct
15 Correct 10 ms 8704 KB Output is correct
16 Correct 10 ms 8704 KB Output is correct
17 Correct 9 ms 8704 KB Output is correct
18 Correct 10 ms 8704 KB Output is correct
19 Correct 10 ms 8704 KB Output is correct
20 Correct 9 ms 8704 KB Output is correct
21 Correct 10 ms 8704 KB Output is correct
22 Correct 10 ms 8640 KB Output is correct
23 Correct 10 ms 8704 KB Output is correct
24 Correct 10 ms 8704 KB Output is correct
25 Correct 10 ms 8704 KB Output is correct
26 Correct 10 ms 8704 KB Output is correct
27 Correct 10 ms 8704 KB Output is correct
28 Correct 10 ms 8704 KB Output is correct
29 Correct 10 ms 8704 KB Output is correct
30 Correct 10 ms 8704 KB Output is correct
31 Correct 11 ms 8704 KB Output is correct
32 Correct 11 ms 8704 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 11 ms 8832 KB Output is correct
2 Correct 12 ms 8864 KB Output is correct
3 Correct 12 ms 8832 KB Output is correct
4 Correct 11 ms 8832 KB Output is correct
5 Correct 13 ms 8832 KB Output is correct
6 Correct 12 ms 8832 KB Output is correct
7 Correct 11 ms 8832 KB Output is correct
8 Correct 14 ms 8832 KB Output is correct
9 Correct 12 ms 8832 KB Output is correct
10 Correct 11 ms 8832 KB Output is correct
11 Correct 11 ms 8832 KB Output is correct
12 Correct 11 ms 8832 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 37 ms 10380 KB Output is correct
2 Correct 34 ms 10388 KB Output is correct
3 Correct 47 ms 10380 KB Output is correct
4 Correct 47 ms 10380 KB Output is correct
5 Correct 33 ms 10384 KB Output is correct
6 Correct 35 ms 10380 KB Output is correct
7 Correct 34 ms 10380 KB Output is correct
8 Correct 27 ms 9884 KB Output is correct
9 Correct 28 ms 9996 KB Output is correct
10 Correct 33 ms 10252 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 386 ms 27356 KB Output is correct
2 Correct 376 ms 27100 KB Output is correct
3 Correct 519 ms 27228 KB Output is correct
4 Correct 494 ms 27232 KB Output is correct
5 Correct 415 ms 27224 KB Output is correct
6 Correct 355 ms 25620 KB Output is correct
7 Correct 399 ms 26260 KB Output is correct
8 Correct 265 ms 21124 KB Output is correct
9 Correct 306 ms 22404 KB Output is correct
10 Correct 424 ms 26332 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Execution timed out 1097 ms 65556 KB Time limit exceeded
2 Halted 0 ms 0 KB -