From 858ef49b59918687c9584c0d550087ed84ab118a Mon Sep 17 00:00:00 2001
From: static <kmc7468@naver.com>
Date: Wed, 30 Oct 2024 04:43:50 +0000
Subject: [PATCH] Assignment 7 Done

---
 src/assignments/assignment07/generator.rs     | 34 ++++++++-
 src/assignments/assignment07/my_itertools.rs  | 65 ++++++++++++-----
 .../assignment07/small_exercises.rs           | 72 +++++++++++++++----
 src/assignments/assignment07/transform.rs     | 19 +++--
 4 files changed, 150 insertions(+), 40 deletions(-)

diff --git a/src/assignments/assignment07/generator.rs b/src/assignments/assignment07/generator.rs
index e92f123..bb359bf 100644
--- a/src/assignments/assignment07/generator.rs
+++ b/src/assignments/assignment07/generator.rs
@@ -24,7 +24,10 @@ impl<T, S> Iterator for Generator<T, S> {
     type Item = T;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        match (self.f)(&mut self.state) {
+            Yielded::Value(v) => Some(v),
+            Yielded::Stop => None,
+        }
     }
 }
 
@@ -32,12 +35,37 @@ impl<T, S> Iterator for Generator<T, S> {
 ///
 /// HINT: Consult <https://en.wikipedia.org/wiki/Fibonacci_sequence>
 pub fn fib_generator(first: usize, second: usize) -> Generator<usize, (usize, usize)> {
-    todo!()
+    Generator {
+        state: (first, second),
+        f: |(a, b)| {
+            let value = *a;
+            *a = *b;
+            *b += value;
+            Yielded::Value(value)
+        },
+    }
 }
 
 /// Returns a generator that yields collatz numbers.
 ///
 /// HINT: Consult <https://en.wikipedia.org/wiki/Collatz_conjecture>
 pub fn collatz_conjecture(start: usize) -> Generator<usize, usize> {
-    todo!()
+    Generator {
+        state: start,
+        f: |start| {
+            let value = *start;
+            if value == 0 {
+                return Yielded::Stop;
+            }
+
+            *start = if value == 1 {
+                0
+            } else if value % 2 == 0 {
+                value / 2
+            } else {
+                3 * value + 1
+            };
+            Yielded::Value(value)
+        },
+    }
 }
diff --git a/src/assignments/assignment07/my_itertools.rs b/src/assignments/assignment07/my_itertools.rs
index 85dae05..7e2653b 100644
--- a/src/assignments/assignment07/my_itertools.rs
+++ b/src/assignments/assignment07/my_itertools.rs
@@ -6,8 +6,8 @@ use std::hash::Hash;
 /// Iterator that iterates over the given iterator and returns only unique elements.
 #[derive(Debug)]
 pub struct Unique<I: Iterator> {
-    // TODO: remove `_marker` and add necessary fields as you want
-    _marker: std::marker::PhantomData<I>,
+    iterator: I,
+    used_values: HashSet<I::Item>,
 }
 
 impl<I: Iterator> Iterator for Unique<I>
@@ -17,15 +17,21 @@ where
     type Item = I::Item;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        for value in self.iterator.by_ref() {
+            if !self.used_values.contains(&value) {
+                let _ = self.used_values.insert(value.clone());
+                return Some(value);
+            }
+        }
+        None
     }
 }
 
 /// Iterator that chains two iterators together.
 #[derive(Debug)]
 pub struct Chain<I1: Iterator, I2: Iterator> {
-    // TODO: remove `_marker` and add necessary fields as you want
-    _marker: std::marker::PhantomData<(I1, I2)>,
+    iterator1: I1,
+    iterator2: I2,
 }
 
 impl<T: Eq + Hash + Clone, I1: Iterator<Item = T>, I2: Iterator<Item = T>> Iterator
@@ -34,22 +40,29 @@ impl<T: Eq + Hash + Clone, I1: Iterator<Item = T>, I2: Iterator<Item = T>> Itera
     type Item = T;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        if let Some(value) = self.iterator1.next() {
+            Some(value)
+        } else {
+            self.iterator2.next()
+        }
     }
 }
 
 /// Iterator that iterates over given iterator and enumerates each element.
 #[derive(Debug)]
 pub struct Enumerate<I: Iterator> {
-    // TODO: remove `_marker` and add necessary fields as you want
-    _marker: std::marker::PhantomData<I>,
+    iterator: I,
+    index: usize,
 }
 
 impl<I: Iterator> Iterator for Enumerate<I> {
     type Item = (usize, I::Item);
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        let value = self.iterator.next()?;
+        let index = self.index;
+        self.index += 1;
+        Some((index, value))
     }
 }
 
@@ -59,15 +72,17 @@ impl<I: Iterator> Iterator for Enumerate<I> {
 /// should be ignored.
 #[derive(Debug)]
 pub struct Zip<I1: Iterator, I2: Iterator> {
-    // TODO: remove `_marker` and add necessary fields as you want
-    _marker: std::marker::PhantomData<(I1, I2)>,
+    iterator1: I1,
+    iterator2: I2,
 }
 
 impl<I1: Iterator, I2: Iterator> Iterator for Zip<I1, I2> {
     type Item = (I1::Item, I2::Item);
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        let value1 = self.iterator1.next()?;
+        let value2 = self.iterator2.next()?;
+        Some((value1, value2))
     }
 }
 
@@ -78,7 +93,10 @@ pub trait MyIterTools: Iterator {
     where
         Self: Sized,
     {
-        todo!()
+        Unique {
+            iterator: self,
+            used_values: HashSet::new(),
+        }
     }
 
     /// Returns an iterator that chains `self` and `other` together.
@@ -86,7 +104,10 @@ pub trait MyIterTools: Iterator {
     where
         Self: Sized,
     {
-        todo!()
+        Chain {
+            iterator1: self,
+            iterator2: other,
+        }
     }
 
     /// Returns an iterator that iterates over `self` and enumerates each element.
@@ -94,7 +115,10 @@ pub trait MyIterTools: Iterator {
     where
         Self: Sized,
     {
-        todo!()
+        Enumerate {
+            iterator: self,
+            index: 0,
+        }
     }
 
     /// Returns an iterator that zips `self` and `other` together.
@@ -102,7 +126,10 @@ pub trait MyIterTools: Iterator {
     where
         Self: Sized,
     {
-        todo!()
+        Zip {
+            iterator1: self,
+            iterator2: other,
+        }
     }
 
     /// Foldleft for `MyIterTools`
@@ -111,7 +138,11 @@ pub trait MyIterTools: Iterator {
         Self: Sized,
         F: FnMut(Self::Item, T) -> T,
     {
-        todo!()
+        let mut result = init;
+        for value in self.by_ref() {
+            result = f(value, result);
+        }
+        result
     }
 }
 
diff --git a/src/assignments/assignment07/small_exercises.rs b/src/assignments/assignment07/small_exercises.rs
index 4555360..d697fff 100644
--- a/src/assignments/assignment07/small_exercises.rs
+++ b/src/assignments/assignment07/small_exercises.rs
@@ -10,7 +10,15 @@ impl<T: Eq> Iterator for FindIter<'_, T> {
     type Item = usize;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        while self.curr + self.query.len() <= self.base.len() {
+            let curr = self.curr;
+            self.curr += 1;
+
+            if &self.base[curr..(curr + self.query.len())] == self.query {
+                return Some(curr);
+            }
+        }
+        None
     }
 }
 
@@ -25,13 +33,13 @@ pub fn find<'s, T: Eq>(query: &'s [T], base: &'s [T]) -> impl 's + Iterator<Item
 
 /// Implement generic fibonacci iterator
 struct FibIter<T> {
-    // TODO: remove `_marker` and add necessary fields as you want
-    _marker: std::marker::PhantomData<T>,
+    first: T,
+    second: T,
 }
 
 impl<T: std::ops::Add<Output = T> + Copy> FibIter<T> {
     fn new(first: T, second: T) -> Self {
-        todo!()
+        Self { first, second }
     }
 }
 
@@ -42,7 +50,10 @@ where
     type Item = T;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        let value = self.first;
+        self.first = self.second;
+        self.second = self.second + value;
+        Some(value)
     }
 }
 
@@ -53,8 +64,7 @@ pub fn fib<T>(first: T, second: T) -> impl Iterator<Item = T>
 where
     T: std::ops::Add<Output = T> + Copy,
 {
-    todo!("replace `std::iter::empty() with your own implementation`");
-    std::iter::empty()
+    FibIter::new(first, second)
 }
 
 /// Endpoint of range, inclusive or exclusive.
@@ -68,12 +78,25 @@ pub enum Endpoint {
 }
 
 struct RangeIter {
-    // TODO: add necessary fields as you want
+    curr: isize,
+    step: isize,
+    last: isize,
 }
 
 impl RangeIter {
     fn new(endpoints: (Endpoint, Endpoint), step: isize) -> Self {
-        todo!()
+        let c = if step > 0 { 1 } else { -1 };
+        Self {
+            curr: match endpoints.0 {
+                Endpoint::Inclusive(v) => v,
+                Endpoint::Exclusive(v) => v + c,
+            },
+            step,
+            last: match endpoints.1 {
+                Endpoint::Inclusive(v) => v,
+                Endpoint::Exclusive(v) => v - c,
+            },
+        }
     }
 }
 
@@ -81,14 +104,19 @@ impl Iterator for RangeIter {
     type Item = isize;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        if self.step > 0 && self.curr > self.last || self.step < 0 && self.curr < self.last {
+            None
+        } else {
+            let value = self.curr;
+            self.curr += self.step;
+            Some(value)
+        }
     }
 }
 
 /// Returns an iterator over the range [left, right) with the given step.
 pub fn range(left: Endpoint, right: Endpoint, step: isize) -> impl Iterator<Item = isize> {
-    todo!("replace `std::iter::empty() with your own implementation`");
-    std::iter::empty()
+    RangeIter::new((left, right), step)
 }
 
 /// Write an iterator that returns all divisors of n in increasing order.
@@ -100,14 +128,27 @@ pub fn range(left: Endpoint, right: Endpoint, step: isize) -> impl Iterator<Item
 /// then n/x is a divisor of n that is smaller than sqrt(n).
 struct Divisors {
     n: u64,
-    // TODO: you may define additional fields here
+    curr: u64,
+    vec: Vec<u64>,
 }
 
 impl Iterator for Divisors {
     type Item = u64;
 
     fn next(&mut self) -> Option<Self::Item> {
-        todo!()
+        while self.curr * self.curr <= self.n {
+            let curr = self.curr;
+            self.curr += 1;
+
+            if self.n % curr == 0 {
+                if curr * curr != self.n {
+                    self.vec.push(self.n / curr);
+                }
+                return Some(curr);
+            }
+        }
+
+        self.vec.pop()
     }
 }
 
@@ -115,6 +156,7 @@ impl Iterator for Divisors {
 pub fn divisors(n: u64) -> impl Iterator<Item = u64> {
     Divisors {
         n,
-        // TODO: you may define additional fields here
+        curr: 1,
+        vec: vec![],
     }
 }
diff --git a/src/assignments/assignment07/transform.rs b/src/assignments/assignment07/transform.rs
index e24588d..a383a68 100644
--- a/src/assignments/assignment07/transform.rs
+++ b/src/assignments/assignment07/transform.rs
@@ -10,7 +10,7 @@ pub trait Transform<T> {
 
 impl<T1, T2, Tr1: Transform<T1>, Tr2: Transform<T2>> Transform<(T1, T2)> for (Tr1, Tr2) {
     fn transform(&self, value: (T1, T2)) -> (T1, T2) {
-        todo!()
+        (self.0.transform(value.0), self.1.transform(value.1))
     }
 }
 
@@ -20,7 +20,7 @@ pub struct Identity;
 
 impl<T> Transform<T> for Identity {
     fn transform(&self, value: T) -> T {
-        todo!()
+        value
     }
 }
 
@@ -42,7 +42,7 @@ impl<T, F: Fn(T) -> T> From<F> for Custom<T, F> {
 
 impl<T, F: Fn(T) -> T> Transform<T> for Custom<T, F> {
     fn transform(&self, value: T) -> T {
-        todo!()
+        (self.f)(value)
     }
 }
 
@@ -67,7 +67,10 @@ impl<T, Tr: Transform<T>> Repeat<T, Tr> {
 
 impl<T, Tr: Transform<T>> Transform<T> for Repeat<T, Tr> {
     fn transform(&self, mut value: T) -> T {
-        todo!()
+        for _ in 0..self.n {
+            value = self.inner.transform(value)
+        }
+        value
     }
 }
 
@@ -90,6 +93,12 @@ impl<T: Clone + Eq, Tr: Transform<T>> RepeatUntilConverge<T, Tr> {
 
 impl<T: Clone + Eq, Tr: Transform<T>> Transform<T> for RepeatUntilConverge<T, Tr> {
     fn transform(&self, mut value: T) -> T {
-        todo!()
+        loop {
+            let old = value.clone();
+            value = self.inner.transform(value);
+            if old == value {
+                return value;
+            }
+        }
     }
 }