finish 65

Author: BaffinLee

65. Valid Number.js

@@ -0,0 +1,66 @@
+/**
+ * 65. Valid Number
+ * 
+ * Validate if a given string is numeric.
+ * 
+ * Some examples:
+ * "0" => true
+ * " 0.1 " => true
+ * "abc" => false
+ * "1 a" => false
+ * "2e10" => true
+ * 
+ * Note: It is intended for the problem statement to be ambiguous. You should gather all requirements up front before implementing one.
+ * 
+ * Update (2015-02-10):
+ * The signature of the C++ function had been updated. If you still see your function signature accepts a const char * argument, please click the reload button to reset your code definition.
+ */
+
+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isNumber = function(s) {
+	var state = [
+			{}, 
+			{'blank': 1, 'sign': 2, 'digit':3, '.':4}, 
+			{'digit':3, '.':4},
+			{'digit':3, '.':5, 'e':6, 'blank':9},
+			{'digit':5},
+			{'digit':5, 'e':6, 'blank':9},
+			{'sign':7, 'digit':8},
+			{'digit':8},
+			{'digit':8, 'blank':9},
+			{'blank':9}
+	];
+	var validState = [3, 5, 8, 9];
+	var currentState = 1;
+	var len = s.length;
+	var str = '';
+	var type = '';
+	for (var i = 0; i < len; i++) {
+			str = s[i];
+			if (str >= '0' && str <= '9') {
+					type = 'digit';
+			} else if (str === '+' || str === '-') {
+					type = 'sign';
+			} else if (str === ' ') {
+					type = 'blank';
+			} else {
+					type = str;
+			}
+			if (state[currentState][type] === undefined) {
+					return false;
+			} else {
+					currentState = state[currentState][type];
+			}
+	}
+	if (validState.indexOf(currentState) === -1) {
+			return false;
+	} else {
+			return true;
+	}
+};
+
+// DFA 确定有限状态自动机
+// https://leetcode.com/problems/valid-number/discuss/23728/A-simple-solution-in-Python-based-on-DFA