feat : palindromic-substrings

Author: ekgns33

palindromic-substrings/ekgns33.java

@@ -0,0 +1,24 @@
+/*
+input : string s
+output: the number of palindromic substrings of given string
+tc : O(n^2) sc : o(n^2) when n is the length of string s
+
+optimize?
+maybe nope.. atleast n^2 to select i and j
+
+ */
+class Solution {
+  public int countSubstrings(String s) {
+    int n = s.length();
+    int cnt = 0;
+    boolean[][] dp = new boolean[n][n];
+    for(int i = n-1; i >= 0; i--) {
+      for(int j = i; j < n; j++) {
+        dp[i][j] = s.charAt(i) == s.charAt(j) && (j-i +1 < 3 || dp[i+1][j-1]);
+        if(dp[i][j]) cnt++;
+      }
+    }
+    return cnt;
+  }
+}
+// Compare this snippet from valid-palindrome-ii/ekgns33.java: