@antv/algorithm
Version:
graph algorithm
78 lines • 2.35 kB
JavaScript
import Queue from './structs/queue';
import { getNeighbors } from './util';
/**
*
* @param callbacks
* allowTraversal: 确定 BFS 是否从顶点沿着边遍历到其邻居，默认情况下，同一个节点只能遍历一次
* enterNode: 当 BFS 访问某个节点时调用
* leaveNode: 当 BFS 访问访问结束某个节点时调用
*/
function initCallbacks(callbacks) {
if (callbacks === void 0) {
callbacks = {};
}
var initiatedCallback = callbacks;
var stubCallback = function stubCallback() {};
var allowTraversalCallback = function () {
var seen = {};
return function (_a) {
var next = _a.next;
var id = next;
if (!seen[id]) {
seen[id] = true;
return true;
}
return false;
};
}();
initiatedCallback.allowTraversal = callbacks.allowTraversal || allowTraversalCallback;
initiatedCallback.enter = callbacks.enter || stubCallback;
initiatedCallback.leave = callbacks.leave || stubCallback;
return initiatedCallback;
}
/**
* 广度优先遍历图
* @param graph Graph 图实例
* @param startNode 开始遍历的节点
* @param originalCallbacks 回调
*/
var breadthFirstSearch = function breadthFirstSearch(graphData, startNodeId, originalCallbacks, directed) {
if (directed === void 0) {
directed = true;
}
var callbacks = initCallbacks(originalCallbacks);
var nodeQueue = new Queue();
var _a = graphData.edges,
edges = _a === void 0 ? [] : _a;
// 初始化队列元素
nodeQueue.enqueue(startNodeId);
var previousNode = '';
var _loop_1 = function _loop_1() {
var currentNode = nodeQueue.dequeue();
callbacks.enter({
current: currentNode,
previous: previousNode
});
// 将所有邻居添加到队列中以便遍历
getNeighbors(currentNode, edges, directed ? 'target' : undefined).forEach(function (nextNode) {
if (callbacks.allowTraversal({
previous: previousNode,
current: currentNode,
next: nextNode
})) {
nodeQueue.enqueue(nextNode);
}
});
callbacks.leave({
current: currentNode,
previous: previousNode
});
// 下一次循环之前存储当前顶点
previousNode = currentNode;
};
// 遍历队列中的所有顶点
while (!nodeQueue.isEmpty()) {
_loop_1();
}
};
export default breadthFirstSearch;