Data commit

Task/Rep-string/Rust/rep-string.rust

@@ -0,0 +1,81 @@
+fn main() {
+    let strings = vec![
+        String::from("1001110011"),
+        String::from("1110111011"),
+        String::from("0010010010"),
+        String::from("1010101010"),
+        String::from("1111111111"),
+        String::from("0100101101"),
+        String::from("0100100"),
+        String::from("101"),
+        String::from("11"),
+        String::from("00"),
+        String::from("1"),
+    ];
+    for string in strings {
+        match rep_string(&string) {
+            Some(rep_string) => println!(
+                "Longuest rep-string for '{}' is '{}' ({} chars)",
+                string,
+                rep_string,
+                rep_string.len(),
+            ),
+            None => println!("No rep-string found for '{}'", string),
+        };
+    }
+}
+
+fn rep_string(string: &str) -> Option<&str> {
+    let index = string.len() / 2;
+
+    for split_index in (1..=index).rev() {
+        let mut is_rep_string = true;
+        let (first, last) = string.split_at(split_index);
+
+        let inter = last.chars().collect::<Vec<char>>();
+        let mut iter = inter.chunks_exact(split_index);
+        for chunk in iter.by_ref() {
+            if first != chunk.iter().collect::<String>() {
+                is_rep_string = false;
+                break;
+            }
+        }
+        let rmnd = iter.remainder().iter().collect::<String>();
+
+        // Check that the remainder starts with the rep-string
+        if !first.starts_with(rmnd.as_str()) {
+            is_rep_string = false;
+        }
+
+        if is_rep_string {
+            return Some(first);
+        }
+    }
+    None
+}
+
+#[cfg(test)]
+mod tests {
+    use super::rep_string;
+    use std::collections::HashMap;
+
+    #[test]
+    fn test_rep_string() {
+        let mut results = HashMap::new();
+        results.insert(String::from("1001110011"), Some("10011"));
+        results.insert(String::from("1110111011"), Some("1110"));
+        results.insert(String::from("0010010010"), Some("001"));
+        results.insert(String::from("1010101010"), Some("1010"));
+        results.insert(String::from("1111111111"), Some("11111"));
+        results.insert(String::from("0100101101"), None);
+        results.insert(String::from("0100100"), Some("010"));
+        results.insert(String::from("101"), None);
+        results.insert(String::from("11"), Some("1"));
+        results.insert(String::from("00"), Some("0"));
+        results.insert(String::from("1"), None);
+
+        for (input, expected) in results {
+            assert_eq!(expected, rep_string(&input));
+        }
+    }
+}