MAJ solution

rust/src/solutions/maj.rs

@@ -0,0 +1,47 @@
+use std::collections::HashMap;
+fn get_maj(a: Vec<u32>) -> i32 {
+    let mut counts = HashMap::new();
+    for &i in &a {
+        let count = counts.entry(i).or_insert(0);
+        *count += 1;
+        if *count > a.len() / 2 {
+            return i as i32;
+        }
+    }
+    -1
+}
+
+pub fn maj(file_content: String) -> String {
+    let lines: Vec<&str> = file_content.lines().collect();
+    let result: Vec<String> = lines[1..]
+        .iter()
+        .map(|x| {
+            let arr: Vec<u32> = x
+                .split(' ')
+                .map(|y| {
+                    y.parse()
+                        .expect("couldn't parse one of the nums in one of the arrays")
+                })
+                .collect();
+            get_maj(arr).to_string()
+        })
+        .collect();
+    result.join(" ")
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_maj() {
+        let input_content = r#"4 8
+5 5 5 5 5 5 5 5
+8 7 7 7 1 7 3 7
+7 1 6 5 10 100 1000 1
+5 1 6 7 1 1 10 1"#
+            .to_string();
+        let expected = "5 7 -1 -1".to_string();
+        assert_eq!(maj(input_content), expected);
+    }
+}

rust/src/solutions/mod.rs

@@ -1,10 +1,12 @@
 mod bins;
 mod iev;
 mod lia;
+mod maj;
 mod prtm;
 mod revp;
 pub use bins::bins;
 pub use iev::iev;
 pub use lia::lia;
+pub use maj::maj;
 pub use prtm::prtm;
 pub use revp::revp;

rust/src/utils.rs

@@ -36,6 +36,7 @@ pub enum Problem {
     IEV,
     LIA,
     BINS,
+    MAJ,
 }
 
 pub fn run_solution(problem: Problem, in_file: &String, out_file: &String) {
@@ -47,6 +48,7 @@ pub fn run_solution(problem: Problem, in_file: &String, out_file: &String) {
             Problem::IEV => Ok(solutions::iev(content)),
             Problem::LIA => Ok(solutions::lia(content)),
             Problem::BINS => Ok(solutions::bins(content)),
+            Problem::MAJ => Ok(solutions::maj(content)),
         },
         Err(e) => Err(e),
     };