diff --git a/problems/0647.回文子串.md b/problems/0647.回文子串.md index 90e6da9f..521c8c26 100644 --- a/problems/0647.回文子串.md +++ b/problems/0647.回文子串.md @@ -267,6 +267,27 @@ class Solution { return ans; } } + +``` + +动态规划:简洁版 +```java +class Solution { + public int countSubstrings(String s) { + boolean[][] dp = new boolean[s.length()][s.length()]; + + int res = 0; + for (int i = s.length() - 1; i >= 0; i--) { + for (int j = i; j < s.length(); j++) { + if (s.charAt(i) == s.charAt(j) && (j - i <= 1 || dp[i + 1][j - 1])) { + res++; + dp[i][j] = true; + } + } + } + return res; + } +} ``` 中心扩散法: