diff --git a/src/jobs.rs b/src/jobs.rs
index d560125..ded07e5 100644
--- a/src/jobs.rs
+++ b/src/jobs.rs
@@ -1,17 +1,48 @@
+use std::cmp::Ordering;
+
 #[derive(Debug)]
 pub struct Job {
-	pub weight: u32,
-	pub length: u32,
+	pub weight: i64,
+	pub length: i64,
 }
 
 pub type Jobs = Vec<Job>;
 
+fn weighted_completion_time(jobs: &Jobs) -> i64 {
+	let mut time = 0;
+	let mut weighted_completion_time = 0;
 
-fn weighted_completion_time(jobs: &Jobs) -> usize {
+	for job in jobs {
+		let completion_time = time + job.length;
+		weighted_completion_time += completion_time * job.weight;
+		time += job.length;
+	}
 
-	jobs.len()
+	weighted_completion_time
 }
 
-pub fn jobs1(jobs: &Jobs) -> usize {
+fn compare_1(a: &Job, b: &Job) -> Ordering {
+	let da = a.weight - a.length;
+	let db = b.weight - b.length;
+	if da == db {
+		b.weight.cmp(&a.weight)
+	} else {
+		db.cmp(&da)
+	}
+}
+
+fn compare_2(a: &Job, b: &Job) -> Ordering {
+	let da: f64 = a.weight as f64 / a.length as f64;
+	let db: f64 = b.weight as f64 / b.length as f64;
+	db.partial_cmp(&da).unwrap()
+}
+
+pub fn jobs_1(jobs: &mut Jobs) -> i64 {
+	jobs.sort_by(compare_1);
 	weighted_completion_time(&jobs)
-}
\ No newline at end of file
+}
+
+pub fn jobs_2(jobs: &mut Jobs) -> i64 {
+	jobs.sort_by(compare_2);
+	weighted_completion_time(&jobs)
+}
diff --git a/src/main.rs b/src/main.rs
index 2ca00ac..9072156 100644
--- a/src/main.rs
+++ b/src/main.rs
@@ -17,7 +17,7 @@ use crate::min_cut::min_cut;
 use crate::quick_sort::quick_sort;
 use crate::ssc::ssc;
 use crate::two_sum::find_two_sums;
-use crate::jobs::jobs1;
+use crate::jobs::{jobs_1, jobs_2};
 use crate::prims::prims;
 
 
@@ -91,12 +91,15 @@ fn c2a4() {
 
 #[allow(dead_code)]
 fn c3a1() {
-	let jobs = util::read_jobs("data/c3a1_jobs.txt").unwrap();
-	let r1 = jobs1(&jobs);
-	let r2 = -1;
-	let r3 = prims();
+	let mut jobs = util::read_jobs("data/c3a1_jobs.txt").unwrap();
+	let r1 = jobs_1(&mut jobs);
+	let r2 = jobs_2(&mut jobs);
+
+	let g = util::read_weighted_graph("data/c3a1_edges.txt").unwrap();
+	let r3 = prims(&g);
 
 	println!("r1 = {}; r2 = {}; r3 = {} ", r1, r2, r3);
+	// r1 = 69119377652; r2 != 67311454237;
 }
 
 fn main() {
diff --git a/src/prims.rs b/src/prims.rs
index bfe7e60..7d9f9ec 100644
--- a/src/prims.rs
+++ b/src/prims.rs
@@ -1,4 +1,14 @@
+#[derive(Debug, Clone)]
 
-pub fn prims() -> usize {
+pub struct Edge {
+	pub node_a: u32,
+	pub node_b: u32,
+	pub weight: u32,
+}
+
+pub type WeightedGraph = Vec<Edge>;
+
+pub fn prims(graph: &WeightedGraph) -> usize {
+	println!("{:?}", graph);
 	42
 }
\ No newline at end of file
diff --git a/src/util.rs b/src/util.rs
index 6524e61..152d5af 100644
--- a/src/util.rs
+++ b/src/util.rs
@@ -3,6 +3,7 @@ use std::io;
 use std::io::{BufRead, BufReader, Error, ErrorKind};
 use std::vec::Vec;
 use crate::jobs::{Job, Jobs};
+use crate::prims::{WeightedGraph, Edge};
 
 #[derive(Debug, Clone)]
 pub struct Graph {
@@ -149,8 +150,8 @@ pub fn read_jobs(path: &str) -> Result<Jobs, io::Error> {
     for line in lines {
         let line = line?;
         let mut nodes = line.split_whitespace();
-        let weight: u32 = nodes.next().unwrap().parse().unwrap();
-        let length: u32 = nodes.next().unwrap().parse().unwrap();
+        let weight = nodes.next().unwrap().parse().unwrap();
+        let length = nodes.next().unwrap().parse().unwrap();
         let job = Job {
             weight: weight,
             length: length,
@@ -160,3 +161,30 @@ pub fn read_jobs(path: &str) -> Result<Jobs, io::Error> {
 
     Ok(jobs)
 }
+
+pub fn read_weighted_graph(path: &str) -> Result<WeightedGraph, io::Error> {
+    let g = Vec::new();
+    let file = File::open(path)?;
+    let br = BufReader::new(file);
+    let mut lines = br.lines();
+    let line = lines.next().unwrap().unwrap();
+    let mut nodes = line.split_whitespace();
+    let n_nodes: usize = nodes.next().unwrap().parse().unwrap();
+    let n_edges: usize = nodes.next().unwrap().parse().unwrap();
+
+    println!("{:?} {:?}", n_nodes, n_edges);
+    // lines.next();
+    // for line in lines {
+    //     let line = line?;
+    //     let mut nodes = line.split_whitespace();
+    //     let weight = nodes.next().unwrap().parse().unwrap();
+    //     let length = nodes.next().unwrap().parse().unwrap();
+    //     let job = Job {
+    //         weight: weight,
+    //         length: length,
+    //     };
+    //     jobs.push(job);
+    // }
+
+    Ok(g)
+}