added job sequening

Author: showmyth

src/greedy/job_sequencing.rs

@@ -0,0 +1,88 @@
+use std::collections::HashMap;
+
+#[derive(Debug, Clone)]
+pub struct Job {
+    pub id: String,
+    pub deadline: usize,
+    pub profit: i32,
+}
+
+pub fn job_sequencing(mut jobs: Vec<Job>) -> (Vec<Job>, i32) {
+    if jobs.is_empty() {
+        return (Vec::new(), 0);
+    }
+
+    // Sort by profit (descending)
+    jobs.sort_by(|a, b| b.profit.cmp(&a.profit));
+
+    // Find the maximum deadline
+    let max_deadline = jobs.iter().map(|j| j.deadline).max().unwrap();
+
+    // Track time slots that are filled
+    let mut slots = vec![false; max_deadline];
+    let mut scheduled = Vec::new();
+    let mut total_profit = 0;
+
+    // Schedule each job in the latest available slot before its deadline is reached
+    for job in jobs {
+        for slot in (0..job.deadline.min(max_deadline)).rev() {
+            if !slots[slot] {
+                slots[slot] = true;
+                scheduled.push(job.clone());
+                total_profit += job.profit;
+                break;
+            }
+        }
+    }
+
+    (scheduled, total_profit)
+}
+
+// test algorithm
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_basic() {
+        let jobs = vec![
+            Job {
+                id: "J1".to_string(),
+                deadline: 2,
+                profit: 100,
+            },
+            Job {
+                id: "J2".to_string(),
+                deadline: 1,
+                profit: 19,
+            },
+            Job {
+                id: "J3".to_string(),
+                deadline: 2,
+                profit: 27,
+            },
+            Job {
+                id: "J4".to_string(),
+                deadline: 1,
+                profit: 25,
+            },
+            Job {
+                id: "J5".to_string(),
+                deadline: 3,
+                profit: 15,
+            },
+        ];
+
+        let (scheduled, profit) = job_sequencing(jobs);
+
+        assert_eq!(profit, 142);
+        assert_eq!(scheduled.len(), 3);
+    }
+
+    #[test]
+    fn test_empty() {
+        let (scheduled, profit) = job_sequencing(vec![]);
+        assert_eq!(profit, 0);
+        assert!(scheduled.is_empty());
+    }
+}

src/greedy/mod.rs

@@ -1,3 +1,5 @@
+mod job_sequencing;
 mod stable_matching;
 
+pub use self::job_sequencing::job_sequencing;
 pub use self::stable_matching::stable_matching;