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Create decodeWays.py

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	`1`	`+`
	`2`	`+`
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	`4`	`+`
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	`6`	`+`
	`7`	`+`
	`8`	`+O(N) time, O(1) space DP via "general fibonacci numbers"`
	`9`	`+class Solution(object):`
	`10`	`+ def numDecodings(self, s):`
	`11`	`+ if len(s) == 0 or s[0] == '0':`
	`12`	`+ return 0`
	`13`	`+ prev, prev_prev = 1, 0`
	`14`	`+ for i in xrange(len(s)):`
	`15`	`+ cur = 0`
	`16`	`+ if s[i] != '0':`
	`17`	`+ cur = prev`
	`18`	`+ if i > 0 and (s[i - 1] == '1' or (s[i - 1] == '2' and s[i] <= '6')):`
	`19`	`+ cur += prev_prev`
	`20`	`+ prev, prev_prev = cur, prev`
	`21`	`+ return prev`
	`22`	`+`
	`23`	`+`

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