Submission #253086

#	Time	Username	Problem	Language	Result	Execution time	Memory
253086		frodakcin	Palindromes (APIO14_palindrome)	C++11	0 / 100	58 ms	58488 KiB

palindrome

#include <cstdio>
#include <cstring>
#include <cassert>
#include <vector>

template<typename T> bool ckmax(T& a, const T& b) {return a<b?a=b,1:0;}

const int MN = 3e5+10;
const int MK = 26;

typedef long long ll;

int N, c[MN][MK], l[MN], d[MN], p, X=1, v[MN];
ll f;
std::vector<int> dw[MN];
char s[MN];
void dfs(int n)
{
	s[n]=1;
	for(auto x:dw[n])
		dfs(x), s[n]+=s[x];
	ckmax(f, (ll)s[n]*d[n]);
}
int main()
{
	scanf(" %s", s+1);
	for(N=1;s[N];++N)s[N]-='a';
	s[0]=-1, s[N--]=-2;
	memset(c, -1, sizeof c);
	d[0]=l[0]=-1, d[1]=l[1]=0;
	dw[0].push_back(1);
	for(int i=1;i<=N;++i)
	{
		for(;s[i]!=s[i-d[p]-1];)p=l[p];
		if(!~c[p][s[i]])
		{
			c[p][s[i]]=++X;
			d[X]=d[p]+2, l[X]=l[p];
			p=X;
			for(;~l[p] && s[i]!=s[i-d[l[p]]-1];l[p]=l[l[p]]);
			if(~l[p] && s[i]==s[i-d[l[p]]-1])
				l[p]=c[l[p]][s[i]];
			else
				l[p]=1;
			assert(~l[p]);
			dw[l[p]].push_back(p);
		}
		else
			p=c[p][s[i]];
		++v[p];
	}
	dfs(0);
	printf("%lld\n", f);
	return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:35:17: warning: array subscript has type 'char' [-Wchar-subscripts]
   if(!~c[p][s[i]])
                 ^
palindrome.cpp:37:13: warning: array subscript has type 'char' [-Wchar-subscripts]
    c[p][s[i]]=++X;
             ^
palindrome.cpp:42:22: warning: array subscript has type 'char' [-Wchar-subscripts]
     l[p]=c[l[p]][s[i]];
                      ^
palindrome.cpp:49:15: warning: array subscript has type 'char' [-Wchar-subscripts]
    p=c[p][s[i]];
               ^
palindrome.cpp:26:7: warning: ignoring return value of 'int scanf(const char*, ...)', declared with attribute warn_unused_result [-Wunused-result]
  scanf(" %s", s+1);
  ~~~~~^~~~~~~~~~~~

• Subtask 1: 0 / 8
• Subtask 2: 0 / 15
• Subtask 3: 0 / 24
• Subtask 4: 0 / 26
• Subtask 5: 0 / 27