Solve two-sum.

source/lib.rs

@@ -0,0 +1 @@
+pub mod two_sum;

source/two_sum/mod.rs

@@ -0,0 +1,26 @@
+use std::convert::TryInto;
+
+pub fn two_sum(numbers: Vec<i32>, target: i32) -> Vec<i32> {
+  for (index_1, number_1) in numbers.iter().enumerate() {
+    for (index_2, number_2) in numbers.iter().enumerate() {
+      if index_1 == index_2 {
+        continue;
+      }
+
+      if number_1 + number_2 == target {
+        return vec![index_1.try_into().unwrap(), index_2.try_into().unwrap()];
+      }
+    }
+  }
+
+  panic!("No pair of numbers found that sum to {}", target)
+}
+
+#[test]
+fn test_two_sum() {
+  assert_eq!(two_sum(vec![2, 7, 11, 15], 9), [0, 1]);
+  assert_eq!(two_sum(vec![3, 2, 4], 6), [1, 2]);
+  assert_eq!(two_sum(vec![3, 3], 6), [0, 1]);
+  assert_eq!(two_sum(vec![3, 2, 3], 6), [0, 2]);
+  assert_eq!(two_sum(vec![-3, 4, 3, 90], 0), [0, 2]);
+}