oj.uz

Submission #312213

# Submission time Handle Problem Language Result Execution time Memory
312213 2020-10-12T18:21:02 Z hohohaha Palindromes (APIO14_palindrome) C++17
73 / 100
 1000 ms 44168 KB 
// DIT ME CUOC DOI 
// Toi noi that la toi deo hieu lam 
// AC tren cses roi nhung tren nay van tle
// Ngu deo chiu dc
#include<bits/stdc++.h>

using namespace std;

#define int long long

#define ii pair<int, int>
#define iii pair<ii, int>

#define mp make_pair
#define eb emplace_back

#define vi vector<int>
#define vii vector<ii>
#define viii vector<iii>

#define fi first
#define se second
#define xx fi.fi
#define yy fi.se
#define zz se
const int max_rank = 300005;
int n, even[max_rank], odd[max_rank], par[max_rank], w[max_rank], ans, mxw, cnt[max_rank];
int prev_idx[max_rank], idx[max_rank], prev_sa[max_rank], sa[max_rank], bucket[max_rank], lcp[max_rank];
string s;
int root(int x)
{
	return par[x]<0? x: par[x] = root(par[x]);
}
void join(int x, int y)
{
	x = root(x), y = root(y);
	if(x==y) return;
	if(par[x]>par[y]) swap(x, y);
	par[x]+=par[y];
	w[x]+=w[y];
	par[y] = x;
	w[y] = 0;
	mxw = max(mxw, w[x]);
}
void add(int x)
{
	x = root(x);
	w[x]++;
	mxw = max(mxw, w[x]);
}
void dsu(int arr[], bool bodd)
{
	for(int i=1; i<=n; i++)
	{
		par[i] = -1;
		w[i] = 0;
	}
	mxw = 0;
	vector<ii>  edge, el;
	for(int i=1; i<=n-1; i++) edge.eb(lcp[i], i);
	for(int i=1; i<=n; i++) el.eb(arr[sa[i]], i);
	sort(begin(edge), end(edge));
	sort(begin(el), end(el));
	int edge_ptr = edge.size(), el_ptr = el.size();
	for(int len = n; len>=1; len--)
	{
		while(el_ptr and el[el_ptr-1].fi>=len)
		{
			add(el[el_ptr-1].se);
			el_ptr--;
		}
		while(edge_ptr and edge[edge_ptr-1].fi>=len) 
		{
			join(edge[edge_ptr-1].se, edge[edge_ptr-1].se+1); // dit me nham thanh .fi moi cay chu
			edge_ptr--;
		}
		ans = max(ans, mxw*(2*len-bodd));
	}
}
signed main()
{
// 	freopen(".inp", "r", stdin);
// 	freopen(".out", "w", stdout);
 	ios_base::sync_with_stdio(false);
    cin.tie(NULL);
    cout.tie(NULL);
    cin>>s; n = s.length();
    s = '$'+s+'$'; n++;
	for(int len = 1; len<=(n<<1); len<<=1) // prev_sa: last suffix array, prev_idx: last rank, sa: idx suffix array, idx: idx rank
	{
		for(int i=1; i<max_rank; i++) cnt[i] = 0;
		if(len==1)
		{
			for(int i=1; i<=n; i++)	cnt[s[i]]++;
			for(int i=1; i<max_rank; i++) cnt[i]+=cnt[i-1];
			for(int i=1; i<=n; i++)	sa[cnt[s[i]]--] = i;
			for(int i=1; i<=n; i++)	idx[sa[i]] = idx[sa[i-1]]+(s[sa[i]]>s[sa[i-1]]);
		}
		else
		{
			int hlf = len>>1;
			for(int i=1; i<=n; i++) prev_idx[i] = idx[i], prev_sa[i] = sa[i];
			for(int i=1; i<=n; i++)	bucket[i] = prev_sa[i]-hlf<1? prev_sa[i]-hlf+n: prev_sa[i]-hlf; 
			for(int i=1; i<=n; i++)	cnt[prev_idx[bucket[i]]]++;
			for(int i=1; i<max_rank; i++) cnt[i]+=cnt[i-1];
			for(int i=n; i>=1; i--) sa[cnt[prev_idx[bucket[i]]]--] = bucket[i];
			for(int i=1; i<=n; i++) 
			{
				if(i==1) idx[sa[i]] = 1;
				else if(prev_idx[sa[i]]==prev_idx[sa[i-1]] 
						and prev_idx[(sa[i]+hlf-1)%n+1]==prev_idx[(sa[i-1]+hlf-1)%n+1]) idx[sa[i]] = idx[sa[i-1]];
				else idx[sa[i]] = idx[sa[i-1]]+1;
			}
		}
	}
	int curl = 0;
	for(int i=1; i<=n; i++)
	{
		if(idx[i]==n) 
		{
			lcp[idx[i]] = 0;
			continue;
		}
		int j = sa[idx[i]+1];
		while(s[i+curl]==s[j+curl])
		{
			curl++;
		}
		lcp[idx[i]] = curl;
		if(curl) curl--;
	}
	int l = 0, r = 0;
	for(int i=1; i<=n; i++)
	{
		if(l<=i and i<=r)
		{
			odd[i] = min(odd[l+r-i], r-i+1);
		}
		while(i-odd[i]>=1 and i+odd[i]<=n and s[i-odd[i]]==s[i+odd[i]]) 
		{
			odd[i]++;
		}
		if(odd[i] and r<i+odd[i]-1)
		{
			r = i+odd[i]-1;
			l = i-odd[i]+1;
		}
	}
	l = 0, r = 0;
	for(int i=2; i<=n; i++)
	{
		if(l<=i-1 and i<=r)
		{
			even[i] = min(even[l+r-i+1], r-i+1); // luc dau quen min o cho nay, toang vai. Nho lan sau phai co!. 
		}
		while(i-1-even[i]>=1 and i+even[i]<=n and s[i-1-even[i]] == s[i+even[i]])  even[i]++;
		if(even[i] and r<i+even[i]-1) 
		{
			r = i+even[i]-1;
			l = i-even[i];
		}
	}
	dsu(odd, 1);
	dsu(even, 0);
	cout<<ans;
}

Compilation message

palindrome.cpp: In function 'int main()':
palindrome.cpp:94:36: warning: array subscript has type 'char' [-Wchar-subscripts]
   94 |    for(int i=1; i<=n; i++) cnt[s[i]]++;
      |                                    ^
palindrome.cpp:96:39: warning: array subscript has type 'char' [-Wchar-subscripts]
   96 |    for(int i=1; i<=n; i++) sa[cnt[s[i]]--] = i;
      |                                       ^

Subtask #1
8.0 / 8.0

# Verdict Execution time Memory Grader output
1 Correct 8 ms 2688 KB Output is correct
2 Correct 6 ms 2688 KB Output is correct
3 Correct 7 ms 2688 KB Output is correct
4 Correct 5 ms 2688 KB Output is correct
5 Correct 5 ms 2688 KB Output is correct
6 Correct 5 ms 2688 KB Output is correct
7 Correct 6 ms 2688 KB Output is correct
8 Correct 6 ms 2688 KB Output is correct
9 Correct 8 ms 2816 KB Output is correct
10 Correct 9 ms 2816 KB Output is correct
11 Correct 8 ms 2688 KB Output is correct
12 Correct 8 ms 2816 KB Output is correct
13 Correct 9 ms 2688 KB Output is correct
14 Correct 10 ms 2816 KB Output is correct
15 Correct 8 ms 2816 KB Output is correct
16 Correct 8 ms 2688 KB Output is correct
17 Correct 8 ms 2688 KB Output is correct
18 Correct 8 ms 2688 KB Output is correct
19 Correct 12 ms 2816 KB Output is correct
20 Correct 12 ms 2816 KB Output is correct
21 Correct 10 ms 2816 KB Output is correct
22 Correct 10 ms 2816 KB Output is correct
23 Correct 11 ms 2816 KB Output is correct
24 Correct 10 ms 2816 KB Output is correct
25 Correct 10 ms 2816 KB Output is correct
26 Correct 10 ms 2816 KB Output is correct
27 Correct 10 ms 2816 KB Output is correct
28 Correct 11 ms 2816 KB Output is correct
29 Correct 10 ms 2816 KB Output is correct
30 Correct 10 ms 2816 KB Output is correct
31 Correct 10 ms 2816 KB Output is correct
32 Correct 11 ms 2816 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 15 ms 2816 KB Output is correct
2 Correct 14 ms 2816 KB Output is correct
3 Correct 14 ms 2944 KB Output is correct
4 Correct 14 ms 2816 KB Output is correct
5 Correct 14 ms 2944 KB Output is correct
6 Correct 14 ms 2944 KB Output is correct
7 Correct 14 ms 2816 KB Output is correct
8 Correct 14 ms 2816 KB Output is correct
9 Correct 14 ms 2944 KB Output is correct
10 Correct 14 ms 2944 KB Output is correct
11 Correct 15 ms 2944 KB Output is correct
12 Correct 14 ms 2828 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 4120 KB Output is correct
2 Correct 26 ms 4120 KB Output is correct
3 Correct 25 ms 4256 KB Output is correct
4 Correct 26 ms 4188 KB Output is correct
5 Correct 26 ms 4128 KB Output is correct
6 Correct 27 ms 4120 KB Output is correct
7 Correct 25 ms 4128 KB Output is correct
8 Correct 26 ms 4188 KB Output is correct
9 Correct 26 ms 4188 KB Output is correct
10 Correct 27 ms 4188 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 113 ms 15056 KB Output is correct
2 Correct 106 ms 15056 KB Output is correct
3 Correct 108 ms 15956 KB Output is correct
4 Correct 119 ms 15828 KB Output is correct
5 Correct 146 ms 15184 KB Output is correct
6 Correct 137 ms 15060 KB Output is correct
7 Correct 122 ms 15440 KB Output is correct
8 Correct 174 ms 15824 KB Output is correct
9 Correct 158 ms 15960 KB Output is correct
10 Correct 162 ms 15952 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 336 ms 41808 KB Output is correct
2 Correct 303 ms 41820 KB Output is correct
3 Correct 311 ms 44128 KB Output is correct
4 Correct 315 ms 44168 KB Output is correct
5 Correct 582 ms 41820 KB Output is correct
6 Correct 380 ms 42476 KB Output is correct
7 Correct 403 ms 42844 KB Output is correct
8 Execution timed out 1097 ms 43572 KB Time limit exceeded
9 Halted 0 ms 0 KB -