n^2 potentially; Iteratively reading prev str

Author: GuanhuiGuan

Count and Say.java

@@ -0,0 +1,25 @@
+class Solution {
+    public String countAndSay(int n) {
+        String prev = "1";
+        for(int i = 1; i < n; i++) {
+            StringBuilder str = new StringBuilder();
+            int count = 0;
+            char prevC = ' ';
+            for(int j = 0; j < prev.length(); j++) {
+                char c = prev.charAt(j);
+                if(j == 0 || c == prevC) {
+                    prevC = c;
+                    count++;
+                }
+                else {
+                    str.append(count).append(prevC);
+                    count = 1;
+                    prevC = c;
+                }
+            }
+            if(count != 0)  str.append(count).append(prevC);
+            prev = str.toString();
+        }
+        return prev;
+    }
+}