add repeated groups implementation (issue #289)

Cargo.lock

@@ -5,3 +5,7 @@ version = 3
 [[package]]
 name = "balance"
 version = "0.1.0"
+
+[[package]]
+name = "repeated-groups"
+version = "0.1.0"

Cargo.toml

@@ -1,4 +1,5 @@
 [workspace]
 members = [
-  "balance"
+  "balance",
+  "repeated-groups",
 ]

repeated-groups/Cargo.toml

@@ -0,0 +1,8 @@
+[package]
+name = "repeated-groups"
+version = "0.1.0"
+edition = "2021"
+
+# See more keys and their definitions at https://doc.rust-lang.org/cargo/reference/manifest.html
+
+[dependencies]

repeated-groups/src/main.rs

@@ -0,0 +1,65 @@
+/// Given a list of numbers, return all groups of repeating consecutive numbers.
+///
+/// Examples:
+///
+/// ```
+/// > repeatedGroups([1, 2, 2, 4, 5])
+/// [[2, 2]]
+///
+/// > repeatedGroups([1, 1, 0, 0, 8, 4, 4, 4, 3, 2, 1, 9, 9])
+/// [[1, 1], [0, 0], [4, 4, 4], [9, 9]]
+/// ```
+
+fn main() {
+    println!("Hello, world!");
+}
+
+fn repeated_groups(nums: Vec<isize>) -> Vec<Vec<isize>> {
+    let mut i = 0;
+    let mut j = 0;
+
+    let mut res: Vec<Vec<isize>> = vec![];
+    let mut curr: Vec<isize> = vec![];
+
+    while j < nums.len() {
+        if nums[i] != nums[j] {
+            if curr.len() > 1 {
+                res.push(curr);
+            }
+
+            i = j;
+            j += 1;
+            curr = vec![nums[i]];
+            continue;
+        }
+
+        curr.push(nums[i]);
+        j += 1;
+    }
+
+    // If the last iteration is a repeated group, the loop exits before appending
+    // the last group to the results, so we check here for what the last group was
+    // and add it to the result if need be.
+    if curr.len() > 1 {
+        res.push(curr);
+    }
+
+    res
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_repeated_groups() {
+        let nums = vec![1, 2, 2, 4, 5];
+        assert_eq!(vec![vec![2, 2]], repeated_groups(nums));
+
+        let nums = vec![1, 1, 0, 0, 8, 4, 4, 4, 3, 2, 1, 9, 9];
+        assert_eq!(
+            vec![vec![1, 1], vec![0, 0], vec![4, 4, 4], vec![9, 9]],
+            repeated_groups(nums)
+        );
+    }
+}