public int countSubstrings(String s) {

int res=0;

boolean dp[][]=new boolean[s.length()][s.length()];

for (int i = 0; i <s.length(); i++) {

for (int j = i; j >-1; j--) { //从i开始 考虑单字符

if (s.charAt(i)==s.charAt(j) &&((i-j)<2||dp[i-1][j+1])){

// (i-j)<2 j=i-1,j=i

dp[i][j]=true;

res++;

}

}

}

return res;

}

/*

public int countSubstrings2(String s) {

int count = 0;

int i;

for(i = 0; i < s.length(); i++){

count += countPalindrome(s, i, i);

count += countPalindrome(s, i, i + 1);

}

return count;

}

public int countPalindrome (String s, int left, int right){

int count = 0;

while(left >= 0 && right < s.length() && s.charAt(left--) == s.charAt(right++)){

count++;

}

return count;

}