报数

yingl · yingl · commit bfa966229668 · 2016-08-04T14:12:46.000+08:00
diff --git a/count_and_say.py b/count_and_say.py
@@ -0,0 +1,29 @@
+# -*- coding: utf-8 -*-
+
+class Solution:
+    # @param {int} n the nth
+    # @return {string} the nth sequence
+    def countAndSay(self, n):
+        # Write your code here
+        return self._countAndSay(n)
+
+    def _countAndSay(self, n):
+        if n == 1:
+            return '1'
+        ret = ''
+        prev_str = self._countAndSay(n - 1)
+        i = 0
+        while i < len(prev_str):
+            ch = prev_str[i]
+            sum = 1
+            j = i + 1
+            while j < len(prev_str):
+                if prev_str[i] == prev_str[j]:
+                    sum += 1
+                    j += 1
+                else:
+                    break
+            ret += str(sum)
+            ret += ch
+            i = j
+        return ret
