From fec9192bf1494a0180ec31388281667c132b7ee6 Mon Sep 17 00:00:00 2001
From: Charles <sircharlesaze@gmail.com>
Date: Thu, 21 May 2020 12:16:03 +0200
Subject: problem 4 5 in rust

---
 rust/004-largest_palindrome_product.rs | 27 +++++++++++++++++++++++++++
 rust/005-smallest_multiple.rs          | 34 ++++++++++++++++++++++++++++++++++
 2 files changed, 61 insertions(+)
 create mode 100644 rust/004-largest_palindrome_product.rs
 create mode 100644 rust/005-smallest_multiple.rs

(limited to 'rust')

diff --git a/rust/004-largest_palindrome_product.rs b/rust/004-largest_palindrome_product.rs
new file mode 100644
index 0000000..c0b49bd
--- /dev/null
+++ b/rust/004-largest_palindrome_product.rs
@@ -0,0 +1,27 @@
+/*
+* Largest palindrome product
+* Problem 4
+*
+* A palindromic number reads the same both ways.
+* The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 × 99.
+* Find the largest palindrome made from the product of two 3-digit numbers.
+*/
+
+fn is_palindrome(n: u32) -> bool {
+    let s: String = n.to_string();
+    let r: String = s.chars().rev().collect();
+    s == r
+}
+
+fn main() {
+    let mut largest = 0;
+
+    for x in 100..1000 {
+        for y in 100..1000 {
+            if is_palindrome(x * y) && x * y > largest{
+                largest = x * y
+            }
+        }
+    }
+    println!("{}", largest);
+}
diff --git a/rust/005-smallest_multiple.rs b/rust/005-smallest_multiple.rs
new file mode 100644
index 0000000..ce671f9
--- /dev/null
+++ b/rust/005-smallest_multiple.rs
@@ -0,0 +1,34 @@
+/*
+* Smallest multiple
+* Problem 5
+*
+* 2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.
+* What is the smallest positive number that is evenly divisible by all of the numbers from 1 to 20?
+*/
+
+fn main() {
+    let mut end = false;
+    let mut n = 2;
+
+    // note to self: iterator are really slow 11s vs 1s without them.
+    loop {
+
+        let mut d = 3;
+        while d <= 20 {
+            if n % d != 0 {
+                end = false;
+                break;
+            } else {
+                end = true;
+            }
+            d += 1;
+        }
+
+        if end {
+            println!("{}", n);
+            break;
+        }
+
+        n += 2;
+    }
+}
-- 
cgit