4th problem part 1 done !

src/prob4/mod.rs

@@ -0,0 +1,40 @@
+fn mutual_inclusion(first_pair: &[u32], second_pair: &[u32]) -> bool {
+    (first_pair[0] <= second_pair[0] && first_pair[1] >= second_pair[1])
+        || (second_pair[0] <= first_pair[0] && second_pair[1] >= first_pair[1])
+}
+
+pub fn solve_part1(file_path: &str) -> i32 {
+    let result = std::fs::read_to_string(file_path)
+        .expect("Please provide a text file as an argument.")
+        .lines()
+        .map(|line| {
+            let tmp = line.split(',').collect::<Vec<&str>>();
+            let firs_pair = tmp
+                .first()
+                .expect("First character error")
+                .split('-')
+                .map(|first_split| {
+                    first_split
+                        .parse::<u32>()
+                        .expect("Parsing number in first pair failed")
+                })
+                .collect::<Vec<u32>>();
+            let second_pair = tmp
+                .last()
+                .expect("First character error")
+                .split('-')
+                .map(|first_split| {
+                    first_split
+                        .parse::<u32>()
+                        .expect("Parsing number in first pair failed")
+                })
+                .collect::<Vec<u32>>();
+            if mutual_inclusion(&firs_pair, &second_pair) {
+                1
+            } else {
+                0
+            }
+        })
+        .collect::<Vec<i32>>();
+    result.iter().sum()
+}