Implement contains

Author: Gianmarco Garrisi

src/double_priority_queue/mod.rs

@@ -760,6 +760,17 @@ where
         self.store.get_priority(item)
     }
 
+    /// Check if the queue contains `item`.
+    ///
+    /// Returns `true` if `item` is in the queue, `false` if it is not.
+    pub fn contains<Q>(&self, item: &Q) -> bool
+    where
+        I: Borrow<Q>,
+        Q: Eq + Hash + ?Sized,
+    {
+        self.store.contains(item)
+    }
+
     /// Get the couple (item, priority) of an arbitrary element, as reference
     /// or `None` if the item is not in the queue.
     pub fn get<Q>(&self, item: &Q) -> Option<(&I, &P)>

src/priority_queue/mod.rs

@@ -635,6 +635,17 @@ where
         self.store.get_priority(item)
     }
 
+    /// Check if the queue contains `item`.
+    ///
+    /// Returns `true` if `item` is in the queue, `false` if it is not.
+    pub fn contains<Q>(&self, item: &Q) -> bool
+    where
+        I: Borrow<Q>,
+        Q: Eq + Hash + ?Sized,
+    {
+        self.store.contains(item)
+    }
+
     /// Get the couple `(item, priority)` of an arbitrary element, as reference
     /// or `None` if the item is not in the queue.
     pub fn get<Q>(&self, item: &Q) -> Option<(&I, &P)>

src/store.rs

@@ -437,6 +437,17 @@ where
         self.map.get(item)
     }
 
+    /// Check if the store contains `item`.
+    ///
+    /// Returns `true` if `item` is in the store, `false` if it is not.
+    pub fn contains<Q>(&self, item: &Q) -> bool
+    where
+        I: Borrow<Q>,
+        Q: Eq + Hash + ?Sized,
+    {
+        self.map.contains_key(item)
+    }
+
     /// Get the couple (item, priority) of an arbitrary element, as reference
     /// or `None` if the item is not in the queue.
     pub fn get<Q>(&self, item: &Q) -> Option<(&I, &P)>

tests/double_priority_queue.rs

@@ -66,6 +66,23 @@ mod doublepq_tests {
         assert_eq!(pq.len(), 3);
     }
 
+    #[test]
+    fn contains() {
+        let mut pq = DoublePriorityQueue::new();
+        assert!(!pq.contains("a"));
+        pq.push("a", 1);
+        pq.push("b", 2);
+        pq.push("f", 7);
+        pq.push("g", 5);
+        pq.push("h", 3);
+
+        assert!(pq.contains("f"));
+
+        pq.pop_max();
+
+        assert!(!pq.contains("f"));
+    }
+
     #[test]
     fn pop_if() {
         let mut pq = DoublePriorityQueue::new();

tests/priority_queue.rs

@@ -101,6 +101,23 @@ mod pqueue_tests {
         assert_eq!(pq.len(), 3);
     }
 
+    #[test]
+    fn contains() {
+        let mut pq = PriorityQueue::new();
+        assert!(!pq.contains("a"));
+        pq.push("a", 1);
+        pq.push("b", 2);
+        pq.push("f", 7);
+        pq.push("g", 5);
+        pq.push("h", 3);
+
+        assert!(pq.contains("f"));
+
+        pq.pop();
+
+        assert!(!pq.contains("f"));
+    }
+
     #[test]
     fn peek_get_mut() {
         use std::hash::{Hash, Hasher};