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Submission #312212

# Submission time Handle Problem Language Result Execution time Memory
312212 2020-10-12T18:15:29 Z hohohaha Palindromes (APIO14_palindrome) C++14
73 / 100
 1000 ms 44256 KB 
#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:90:36: warning: array subscript has type 'char' [-Wchar-subscripts]
   90 |    for(int i=1; i<=n; i++) cnt[s[i]]++;
      |                                    ^
palindrome.cpp:92:39: warning: array subscript has type 'char' [-Wchar-subscripts]
   92 |    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 7 ms 2688 KB Output is correct
2 Correct 6 ms 2816 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 2688 KB Output is correct
10 Correct 8 ms 2688 KB Output is correct
11 Correct 8 ms 2816 KB Output is correct
12 Correct 8 ms 2688 KB Output is correct
13 Correct 9 ms 2816 KB Output is correct
14 Correct 10 ms 2688 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 2816 KB Output is correct
19 Correct 10 ms 2816 KB Output is correct
20 Correct 10 ms 2816 KB Output is correct
21 Correct 10 ms 2816 KB Output is correct
22 Correct 11 ms 2816 KB Output is correct
23 Correct 10 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 10 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 10 ms 2816 KB Output is correct

Subtask #2
15.0 / 15.0

# Verdict Execution time Memory Grader output
1 Correct 16 ms 2816 KB Output is correct
2 Correct 14 ms 2832 KB Output is correct
3 Correct 14 ms 2944 KB Output is correct
4 Correct 14 ms 2944 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 14 ms 2944 KB Output is correct
12 Correct 14 ms 2832 KB Output is correct

Subtask #3
24.0 / 24.0

# Verdict Execution time Memory Grader output
1 Correct 26 ms 4128 KB Output is correct
2 Correct 25 ms 4128 KB Output is correct
3 Correct 25 ms 4180 KB Output is correct
4 Correct 25 ms 4188 KB Output is correct
5 Correct 26 ms 4128 KB Output is correct
6 Correct 27 ms 4128 KB Output is correct
7 Correct 25 ms 4120 KB Output is correct
8 Correct 26 ms 4188 KB Output is correct
9 Correct 27 ms 4308 KB Output is correct
10 Correct 27 ms 4180 KB Output is correct

Subtask #4
26.0 / 26.0

# Verdict Execution time Memory Grader output
1 Correct 112 ms 15060 KB Output is correct
2 Correct 108 ms 15064 KB Output is correct
3 Correct 108 ms 15952 KB Output is correct
4 Correct 116 ms 15828 KB Output is correct
5 Correct 144 ms 15056 KB Output is correct
6 Correct 133 ms 15104 KB Output is correct
7 Correct 121 ms 15440 KB Output is correct
8 Correct 175 ms 15948 KB Output is correct
9 Correct 160 ms 15956 KB Output is correct
10 Correct 161 ms 16068 KB Output is correct

Subtask #5
0 / 27.0

# Verdict Execution time Memory Grader output
1 Correct 336 ms 41832 KB Output is correct
2 Correct 302 ms 41832 KB Output is correct
3 Correct 312 ms 44132 KB Output is correct
4 Correct 314 ms 44256 KB Output is correct
5 Correct 532 ms 41832 KB Output is correct
6 Correct 391 ms 42460 KB Output is correct
7 Correct 392 ms 42956 KB Output is correct
8 Execution timed out 1089 ms 44160 KB Time limit exceeded
9 Halted 0 ms 0 KB -