参考答案

参考回答:

int LongestPalindromicSubstring(string & a)
{
int len = a.length();
vector<vector<int>>dp(len, vector<int>(len, 0));
for (int i = 0; i < len; i++)
{
dp[i][i] = 1;
}
int max_len = 1;
int start_index = 0;
for (int i= len - 2; i >= 0; i--)
{
for (int j = i + 1; j < len; j++)
{
if (a[i] == a[j])
{
if (j - i == 1)
{
dp[i][j] = 2;
}
else
{
if (j - i > 1)
{
dp[i][j] = dp[i + 1][j - 1] + 2;
}
}
if (max_len < dp[i][j])
{
max_len =  dp[i][j];
start_index = i;
}
}
else
{
dp[i][j] = 0;
}
}
}
cout << "max len is " << max_len << endl;
cout << "star index is" << start_index << endl;
return max_len;
}