Initial commit

1 files changed, 33 insertions, 0 deletions

diff --git a/src/lib.rs b/src/lib.rs
new file mode 100644
index 0000000..eead58f
--- /dev/null
+++ b/src/lib.rs
@@ -0,0 +1,33 @@
+pub fn brutal(arr: &[usize]) -> Option<usize> {
+    let sum: usize = arr.iter().sum();
+
+    let x = arr
+        .iter()
+        .enumerate()
+        .try_fold((0, sum), |(left, right), (idx, x)| {
+            if left == right - x {
+                Err(idx)
+            } else {
+                Ok((left + x, right - x))
+            }
+        });
+
+    if let Err(idx) = x { Some(idx) } else { None }
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+    use test_case::test_case;
+
+    #[test_case(&[1, 1, 1, 2],  2)]
+    #[test_case(&[1, 2, 3, 6, 3, 3],  3)]
+    #[test_case(&[0, 1, 0],  1)]
+    #[test_case(&[0, 0, 0],  0)]
+    #[test_case(&[4, 1000, 1, 1, 1, 1],  1)]
+    fn test(arr: &[usize], expected_idx: usize) {
+        let idx = brutal(arr);
+
+        assert_eq!(idx, Some(expected_idx));
+    }
+}