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[Rust] No need to use mut iter (#1356)

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* No need to use mut iter

* Update iter
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rongyi 2024-05-12 14:49:25 +08:00 committed by GitHub
parent ebff1cce9f
commit 063a41fa7f
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2 changed files with 10 additions and 12 deletions
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6
codes/rust/chapter_sorting/bucket_sort.rs
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@ -12,7 +12,7 @@ fn bucket_sort(nums: &mut [f64]) {
let k = nums.len() / 2; let k = nums.len() / 2;
let mut buckets = vec![vec![]; k]; let mut buckets = vec![vec![]; k];
// 1. 将数组元素分配到各个桶中 // 1. 将数组元素分配到各个桶中
for &mut num in &mut *nums { for &num in nums.iter() {
// 输入数据范围为 [0, 1)，使用 num * k 映射到索引范围 [0, k-1] // 输入数据范围为 [0, 1)，使用 num * k 映射到索引范围 [0, k-1]
let i = (num * k as f64) as usize; let i = (num * k as f64) as usize;
// 将 num 添加进桶 i // 将 num 添加进桶 i
@ -25,8 +25,8 @@ fn bucket_sort(nums: &mut [f64]) {
} }
// 3. 遍历桶合并结果 // 3. 遍历桶合并结果
let mut i = 0; let mut i = 0;
for bucket in &mut buckets { for bucket in buckets.iter() {
for &mut num in bucket { for &num in bucket.iter() {
nums[i] = num; nums[i] = num;
i += 1; i += 1;
} }

16
codes/rust/chapter_sorting/counting_sort.rs
View file

@ -10,11 +10,11 @@ include!("../include/include.rs");
// 简单实现，无法用于排序对象 // 简单实现，无法用于排序对象
fn counting_sort_naive(nums: &mut [i32]) { fn counting_sort_naive(nums: &mut [i32]) {
// 1. 统计数组最大元素 m // 1. 统计数组最大元素 m
let m = *nums.into_iter().max().unwrap(); let m = *nums.iter().max().unwrap();
// 2. 统计各数字的出现次数 // 2. 统计各数字的出现次数
// counter[num] 代表 num 的出现次数 // counter[num] 代表 num 的出现次数
let mut counter = vec![0; m as usize + 1]; let mut counter = vec![0; m as usize + 1];
for &num in &*nums { for &num in nums.iter() {
counter[num as usize] += 1; counter[num as usize] += 1;
} }
// 3. 遍历 counter ，将各元素填入原数组 nums // 3. 遍历 counter ，将各元素填入原数组 nums
@ -31,16 +31,16 @@ fn counting_sort_naive(nums: &mut [i32]) {
// 完整实现，可排序对象，并且是稳定排序 // 完整实现，可排序对象，并且是稳定排序
fn counting_sort(nums: &mut [i32]) { fn counting_sort(nums: &mut [i32]) {
// 1. 统计数组最大元素 m // 1. 统计数组最大元素 m
let m = *nums.into_iter().max().unwrap(); let m = *nums.iter().max().unwrap() as usize;
// 2. 统计各数字的出现次数 // 2. 统计各数字的出现次数
// counter[num] 代表 num 的出现次数 // counter[num] 代表 num 的出现次数
let mut counter = vec![0; m as usize + 1]; let mut counter = vec![0; m + 1];
for &num in &*nums { for &num in nums.iter() {
counter[num as usize] += 1; counter[num as usize] += 1;
} }
// 3. 求 counter 的前缀和，将“出现次数”转换为“尾索引” // 3. 求 counter 的前缀和，将“出现次数”转换为“尾索引”
// 即 counter[num]-1 是 num 在 res 中最后一次出现的索引 // 即 counter[num]-1 是 num 在 res 中最后一次出现的索引
for i in 0..m as usize { for i in 0..m {
counter[i + 1] += counter[i]; counter[i + 1] += counter[i];
} }
// 4. 倒序遍历 nums ，将各元素填入结果数组 res // 4. 倒序遍历 nums ，将各元素填入结果数组 res
@ -53,9 +53,7 @@ fn counting_sort(nums: &mut [i32]) {
counter[num as usize] -= 1; // 令前缀和自减 1 ，得到下次放置 num 的索引 counter[num as usize] -= 1; // 令前缀和自减 1 ，得到下次放置 num 的索引
} }
// 使用结果数组 res 覆盖原数组 nums // 使用结果数组 res 覆盖原数组 nums
for i in 0..n { nums.copy_from_slice(&res)
nums[i] = res[i];
}
} }
/* Driver Code */ /* Driver Code */