颠倒给定的 32 位无符号整数的二进制位。
示例 1:
输入: 00000010100101000001111010011100
输出: 00111001011110000010100101000000
解释: 输入的二进制串 00000010100101000001111010011100 表示无符号整数 43261596,
因此返回 964176192,其二进制表示形式为 00111001011110000010100101000000。
示例 2:
输入:11111111111111111111111111111101
输出:10111111111111111111111111111111
解释:输入的二进制串 11111111111111111111111111111101 表示无符号整数 4294967293,
因此返回 3221225471 其二进制表示形式为 10101111110010110010011101101001。
提示:
请注意,在某些语言(如 Java)中,没有无符号整数类型。在这种情况下,输入和输出都将被指定为有符号整数类型,并且不应影响您的实现,因为无论整数是有符号的还是无符号的,其内部的二进制表示形式都是相同的。在 Java 中,编译器使用二进制补码记法来表示有符号整数。因此,在上面的 示例 2 中,输入表示有符号整数 -3,输出表示有符号整数 -1073741825。
进阶: 如果多次调用这个函数,你将如何优化你的算法?
来源:力扣(LeetCode) 链接:https://leetcode-cn.com/problems/reverse-bits 著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。
这道题是给定一个32位的无符号整型,让你按位翻转, 第一位变成最后一位, 第二位变成倒数第二位。。。
那么思路就是 双指针
这个指针可以加引号
n>>>0
/*
* @lc app=leetcode id=190 lang=javascript
*
* [190] Reverse Bits
*
* https://leetcode.com/problems/reverse-bits/description/
*
* algorithms
* Easy (30.30%)
* Total Accepted: 173.7K
* Total Submissions: 568.2K
* Testcase Example: '00000010100101000001111010011100'
*
* Reverse bits of a given 32 bits unsigned integer.
*
*
*
* Example 1:
*
*
* Input: 00000010100101000001111010011100
* Output: 00111001011110000010100101000000
* Explanation: The input binary string 00000010100101000001111010011100
* represents the unsigned integer 43261596, so return 964176192 which its
* binary representation is 00111001011110000010100101000000.
*
*
* Example 2:
*
*
* Input: 11111111111111111111111111111101
* Output: 10111111111111111111111111111111
* Explanation: The input binary string 11111111111111111111111111111101
* represents the unsigned integer 4294967293, so return 3221225471 which its
* binary representation is 10101111110010110010011101101001.
*
*
*
* Note:
*
*
* Note that in some languages such as Java, there is no unsigned integer type.
* In this case, both input and output will be given as signed integer type and
* should not affect your implementation, as the internal binary representation
* of the integer is the same whether it is signed or unsigned.
* In Java, the compiler represents the signed integers using 2's complement
* notation. Therefore, in Example 2 above the input represents the signed
* integer -3 and the output represents the signed integer -1073741825.
*
*
*
*
* Follow up:
*
* If this function is called many times, how would you optimize it?
*
*/
/**
* @param {number} n - a positive integer
* @return {number} - a positive integer
*/
var reverseBits = function(n) {
let res = 0;
for (let i = 0; i < 32; i++) {
res = (res << 1) + (n & 1);
n = n >>> 1;
}
return res >>> 0;
};