91. Decode Ways

/**
 * @param {string} s
 * @return {number}
 */
var numDecodings = function (s) {
	if (!s || s[0] === '0') return 0
	const recurse = (len) => {
		if (len === 0 || len === 1) return 1
		let count = 0
		if (s[len - 1] > '0') {
			count += recurse(len - 1)
		}
		if (s[len - 2] === '1' || (s[len - 2] === '2' && s[len - 1] < '7')) {
			count += recurse(len - 2)
		}
		return count
	}
	return recurse(s.length)
}

const testCases = ['0', '226134', '17', '226']
testCases.forEach((item) => {
	//Test cases
	console.log(numDecodings(item))
})