carloscn / structstudy

Leetcode daily trainning by using C/C++/RUST programming.
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leetcode2293: Min Max Game #376

Open carloscn opened 11 months ago

carloscn commented 11 months ago

Description

You are given a 0-indexed integer array nums whose length is a power of 2.

Apply the following algorithm on nums:

Let n be the length of nums. If n == 1, end the process. Otherwise, create a new 0-indexed integer array newNums of length n / 2. For every even index i where 0 <= i < n / 2, assign the value of newNums[i] as min(nums[2 i], nums[2 i + 1]). For every odd index i where 0 <= i < n / 2, assign the value of newNums[i] as max(nums[2 i], nums[2 i + 1]). Replace the array nums with newNums. Repeat the entire process starting from step 1. Return the last number that remains in nums after applying the algorithm.

Example 1:

image

Input: nums = [1,3,5,2,4,8,2,2] Output: 1 Explanation: The following arrays are the results of applying the algorithm repeatedly. First: nums = [1,5,4,2] Second: nums = [1,4] Third: nums = [1] 1 is the last remaining number, so we return 1.

Example 2:

Input: nums = [3] Output: 3 Explanation: 3 is already the last remaining number, so we return 3.

Constraints:

1 <= nums.length <= 1024 1 <= nums[i] <= 109 nums.length is a power of 2.

carloscn commented 11 months ago

Analysis

pub fn min_max_game(nums: Vec<i32>) -> i32
{
    let mut ret:i32 = 0;

    if nums.len() == 0 {
        return ret;
    }

    let mut array:Vec<i32> = nums.clone();

    while array.len() != 1 {
        let mut j:usize = 0;
        let mut i:usize = 1;
        let mut t_buf:Vec<i32> = vec![];
        while i < array.len() {
            let e:i32;
            if (j & 0x1) == 0 {
                e = array[i].min(array[i - 1]);
            } else {
                e = array[i].max(array[i - 1]);
            }
            t_buf.push(e);
            j += 1;
            i = 2 * i + 1;
        }
        array = t_buf;
    }

    ret = array[0];

    return ret;
}
carloscn commented 11 months ago

Code

https://review.gerrithub.io/c/carloscn/structstudy/+/1170566 https://github.com/carloscn/structstudy/commit/840756f31f92dbde2d8ed5c9e3149d200615a0ea