Update solution 007 solution.js [JavaScript]

Author: Mcnwork2018

solution/007.Reverse Integer/Solution.js

@@ -0,0 +1,33 @@
+/**
+ * @param {number} x
+ * @return {number}
+ */
+
+/**
+ *  First Way：将数字转化为字符串的处理
+ */
+var reverse = function(x) {
+  const min = -Math.pow(2,31),max = Math.pow(2,31) - 1;
+  let sign = 1;
+  if(x < 0){
+      sign = -sign;
+      x = sign * x;
+  }
+  let a = x.toString();
+  let len = a.length,b='';
+  for(let i = len - 1;i >= 0;i--)b+=a[i];
+  b = sign * Number(b);
+  if(b > max || b < min) return 0;
+  return b;
+};
+/** 
+ *  Second Way: 弹出和推入数字
+ */
+let reverse = function(x) {
+  let res = 0;
+  while (x !== 0) {
+      res = res * 10 + x % 10;
+      x = x < 0 ? Math.ceil(x / 10) : Math.floor(x / 10);
+  }
+  return res < -(2**31) || res > 2**31 - 1 ? 0 : res;
+};