carloscn / structstudy

Leetcode daily trainning by using C/C++/RUST programming.
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leetcode1356:根据数字二进制下 1 的数目排序(sort-integers-by-the-number-of-1-bits) #214

Open carloscn opened 1 year ago

carloscn commented 1 year ago

问题描述

给你一个整数数组 arr 。请你将数组中的元素按照其二进制表示中数字 1 的数目升序排序。

如果存在多个数字二进制中 1 的数目相同,则必须将它们按照数值大小升序排列。

请你返回排序后的数组。

 

示例 1:

输入:arr = [0,1,2,3,4,5,6,7,8] 输出:[0,1,2,4,8,3,5,6,7] 解释:[0] 是唯一一个有 0 个 1 的数。 [1,2,4,8] 都有 1 个 1 。 [3,5,6] 有 2 个 1 。 [7] 有 3 个 1 。 按照 1 的个数排序得到的结果数组为 [0,1,2,4,8,3,5,6,7]

示例 2:

输入:arr = [1024,512,256,128,64,32,16,8,4,2,1] 输出:[1,2,4,8,16,32,64,128,256,512,1024] 解释:数组中所有整数二进制下都只有 1 个 1 ,所以你需要按照数值大小将它们排序。

示例 3:

输入:arr = [10000,10000] 输出:[10000,10000]

示例 4:

输入:arr = [2,3,5,7,11,13,17,19] 输出:[2,3,5,17,7,11,13,19]

示例 5:

输入:arr = [10,100,1000,10000] 输出:[10,100,10000,1000]  

提示:

1 <= arr.length <= 500 0 <= arr[i] <= 10^4

来源:力扣(LeetCode) 链接:https://leetcode.cn/problems/sort-integers-by-the-number-of-1-bits

carloscn commented 1 year ago

问题分析

fn count_bit_1(num:i32) -> i32
{
    let mut e = num;
    let mut ret:i32 = 0;

    while e != 0 {
        if e & 1 == 1 {
            ret += 1;
        }
        e >>= 1;
    }

    return ret;
}

pub fn sort_by_bits(arr: Vec<i32>) -> Vec<i32>
{
    if arr.len() < 1 {
        return arr;
    }

    let mut ret:Vec<i32> = arr.clone();

    for i in 0..ret.len() {
        for j in 0..(ret.len() - i - 1) {
            let count_a = count_bit_1(ret[j]);
            let count_b = count_bit_1(ret[j + 1]);
            if (count_a > count_b) ||
               ((count_a == count_b) && (ret[j] > ret[j + 1])) {
                ret[j] ^= ret[j+1];
                ret[j+1] ^= ret[j];
                ret[j] ^= ret[j+1];
            }
        }
    }

    return ret;
}
carloscn commented 1 year ago

code

https://review.gerrithub.io/c/carloscn/structstudy/+/553686 https://github.com/carloscn/structstudy/commit/8c9c0ec6cfcb8a3388999df41f6b39c7634864af