693. Binary Number with Alternating Bits 交替位的二进制数

Given a positive integer, check whether it has alternating bits: namely, if two adjacent bits will always have different values.

Example 1:

Input: 5
Output: True
Explanation:
The binary representation of 5 is: 101

Example 2:

Input: 7
Output: False
Explanation:
The binary representation of 7 is: 111.

Example 3:

Input: 11
Output: False
Explanation:
The binary representation of 11 is: 1011.

Example 4:

Input: 10
Output: True
Explanation:
The binary representation of 10 is: 1010.

给定正整数，检查它的二进制数是否具有交替位：即，如果两个相邻位总是具有不同的值。

/**
 * @param {number} n
 * @return {boolean}
 */
var hasAlternatingBits = function(n) {
    let str = n.toString(2);
    let bit = -1;
    let index = 0;
    while (index < str.length) {
        if (bit == -1) {
            bit = str[index++];
        } else {
            if (str[index++] == bit) {
                return false;
            } else {
                bit = !bit;
            }
        }
    }
    return true;
};

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