| ... | ... | @@ -4,6 +4,7 @@ const debug = std.debug; |
| 4 | 4 | const expect = std.testing.expect; |
| 5 | 5 | const expectEqual = std.testing.expectEqual; |
| 6 | 6 | |
| 7 | /// Priority queue for storing generic data. Initialize with `init`. |
| 7 | 8 | pub fn PriorityQueue(comptime T: type) type { |
| 8 | 9 | return struct { |
| 9 | 10 | const Self = @This(); |
| ... | ... | @@ -13,6 +14,12 @@ pub fn PriorityQueue(comptime T: type) type { |
| 13 | 14 | allocator: *Allocator, |
| 14 | 15 | compareFn: fn (a: T, b: T) bool, |
| 15 | 16 | |
| 17 | /// Initialize and return a priority queue. Provide |
| 18 | /// `compareFn` that returns `true` when its first argument |
| 19 | /// should get popped before its second argument. For example, |
| 20 | /// to make `pop` return the minimum value, provide |
| 21 | /// |
| 22 | /// `fn lessThan(a: T, b: T) bool { return a < b; }` |
| 16 | 23 | pub fn init(allocator: *Allocator, compareFn: fn (a: T, b: T) bool) Self { |
| 17 | 24 | return Self{ |
| 18 | 25 | .items = [_]T{}, |
| ... | ... | @@ -22,10 +29,12 @@ pub fn PriorityQueue(comptime T: type) type { |
| 22 | 29 | }; |
| 23 | 30 | } |
| 24 | 31 | |
| 32 | /// Free memory used by the queue. |
| 25 | 33 | pub fn deinit(self: Self) void { |
| 26 | 34 | self.allocator.free(self.items); |
| 27 | 35 | } |
| 28 | 36 | |
| 37 | /// Insert a new element, maintaining priority. |
| 29 | 38 | pub fn add(self: *Self, elem: T) !void { |
| 30 | 39 | try ensureCapacity(self, self.len + 1); |
| 31 | 40 | addUnchecked(self, elem); |
| ... | ... | @@ -48,6 +57,7 @@ pub fn PriorityQueue(comptime T: type) type { |
| 48 | 57 | self.len += 1; |
| 49 | 58 | } |
| 50 | 59 | |
| 60 | /// Add each element in `items` to the queue. |
| 51 | 61 | pub fn addSlice(self: *Self, items: []const T) !void { |
| 52 | 62 | try self.ensureCapacity(self.len + items.len); |
| 53 | 63 | for (items) |e| { |
| ... | ... | @@ -55,10 +65,14 @@ pub fn PriorityQueue(comptime T: type) type { |
| 55 | 65 | } |
| 56 | 66 | } |
| 57 | 67 | |
| 68 | /// Look at the highest priority element in the queue. Returns |
| 69 | /// `null` if empty. |
| 58 | 70 | pub fn peek(self: *Self) ?T { |
| 59 | 71 | return if (self.len > 0) self.items[0] else null; |
| 60 | 72 | } |
| 61 | 73 | |
| 74 | /// Pop the highest priority element from the queue. Returns |
| 75 | /// `null` if empty. |
| 62 | 76 | pub fn removeOrNull(self: *Self) ?T { |
| 63 | 77 | return if (self.len > 0) self.remove() else null; |
| 64 | 78 | } |
| ... | ... | @@ -72,10 +86,14 @@ pub fn PriorityQueue(comptime T: type) type { |
| 72 | 86 | return first; |
| 73 | 87 | } |
| 74 | 88 | |
| 89 | /// Return the number of elements remaining in the priority |
| 90 | /// queue. |
| 75 | 91 | pub fn count(self: Self) usize { |
| 76 | 92 | return self.len; |
| 77 | 93 | } |
| 78 | 94 | |
| 95 | /// Return the number of elements that can be added to the |
| 96 | /// queue before more memory is allocated. |
| 79 | 97 | pub fn capacity(self: Self) usize { |
| 80 | 98 | return self.items.len; |
| 81 | 99 | } |
| ... | ... | @@ -171,6 +189,8 @@ pub fn PriorityQueue(comptime T: type) type { |
| 171 | 189 | } |
| 172 | 190 | }; |
| 173 | 191 | |
| 192 | /// Return an iterator that walks the queue without consuming |
| 193 | /// it. Invalidated if the heap is modified. |
| 174 | 194 | pub fn iterator(self: *Self) Iterator { |
| 175 | 195 | return Iterator{ |
| 176 | 196 | .queue = self, |
Andrew Kelley <andrew@ziglang.org> 2019-10-30 20:43:56-04:00
Commit is signed but in an unrecognized format.
lib