Submission #251373

#	Time	Username	Problem	Language	Result	Execution time	Memory
251373		phuleethanh	Palindromes (APIO14_palindrome)	C++14	0 / 100	1091 ms	5108 KiB

palindrome

#include <bits/stdc++.h>
using namespace std;
struct nut
{
    int len = 0, num = 0, suffLink = 0, child[26] = {0}, nlen = 0;
};
int curNode;
vector<nut> Tree;
string s;

void initPalinTree()
{
    Tree.emplace_back();
    Tree[0].len = 0, Tree[0].suffLink = 1;
    Tree.emplace_back();
    Tree[1].len = -1, Tree[1].suffLink = 1;
    curNode = 0;
}

bool insert(int i)
{
    int w = s[i] - 'a';
    int x = curNode;
    while (1)
    {
        int k = Tree[x].len;
        if (i - k - 1 >= 0 && s[i - k - 1] == s[i])
            break;
        x = Tree[x].suffLink;
    }
    if (Tree[x].child[w])
        return curNode = Tree[x].child[w], 0;
    curNode = Tree.size();
    Tree.emplace_back();
    Tree[x].child[w] = curNode;
    Tree[curNode].len = Tree[x].len + 2;
    Tree[curNode].nlen = 1;
    Tree[curNode].num = 1;
    if (Tree[curNode].len == 1)
        return Tree[curNode].suffLink = 0, 1;
    while (1)
    {
        x = Tree[x].suffLink;
        int k = Tree[x].len;
        if (i - k - 1 >= 0 && s[i - k - 1] == s[i])
            break;
    }
    Tree[curNode].suffLink = Tree[x].child[w];
    Tree[curNode].num = Tree[Tree[curNode].suffLink].num + 1;
    return 1;
}

void capnhatnguoc(int x)
{
    while (x > 1) //Khi nao con khac hai nut goc
    {
        x = Tree[x].suffLink; //di nguoc len nut suffLink
        if (x > 1)
            Tree[x].nlen++;
    }
}

int main()
{
    //freopen("z.inp", "r", stdin);
    ios::sync_with_stdio(0), cin.tie(0), cout.tie(0);
    initPalinTree();
    cin >> s;
    for (int i = 0; i < s.size(); i++)
    {
        insert(i);
        capnhatnguoc(curNode);
    }
    long long ans = 1;
    for (auto x : Tree)
        ans = max(ans, 1ll * x.len * x.nlen);
    cout << ans;
    return 0;
}

Compilation message (stderr)

palindrome.cpp: In function 'int main()':
palindrome.cpp:69:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare]
     for (int i = 0; i < s.size(); i++)
                     ~~^~~~~~~~~~

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