在数组的Map中不使用图查找循环依赖

Question

我有如下对象：

var myMap = {
    v1: ['v2', 'v4', 'v5'],
    v2: ['x', 'v4', 'y'],
    v3: ['v2', 'v4', 'v5'],
    v4: ['e', 'v1', 'v5'],
    v5: ['v2', 'v4', 'v3'],
};

我必须在不将其转换为图形的情况下找到循环实体图。

喜欢的输出将如下所示：

var myDep = {
    v1: {isCyclic: true, cyclicDependents: ['v4']},
    v2: {isCyclic: false, cyclicDependents: []},
    v3: {isCyclic: true, cyclicDependents: ['v5']},
    v4: {isCyclic: true, cyclicDependents: ['v1', 'v5']},
    v5: {isCyclic: true, cyclicDependents: ['v4', 'v3']},
};

我试过以下方法：

var graph = {
  v1: ["v2", "v4", "v5"],
  v2: ["x", "v4", "y"],
  v3: ["v2", "v4", "v5"],
  v4: ["e", "v1", "v5"],
  v5: ["v2", "v4", "v3"]
};

var myDep = {
  v1: { isCyclic: false, cyclicDependents: [] },
  v2: { isCyclic: false, cyclicDependents: [] },
  v3: { isCyclic: false, cyclicDependents: [] },
  v4: { isCyclic: false, cyclicDependents: [] },
  v5: { isCyclic: false, cyclicDependents: [] }
};

myDep = Object.keys(graph).reduce((a, b) => {
  graph[b] &&
graph[b].forEach(d => {
  if (graph[d] && ~graph[d].indexOf(b)) {
    a[b].isCyclic = true;
    a[b].cyclicDependents.push(d);
  }
});
  return a;
}, myDep);

console.log(myDep);

有没有其他方法可以提高性能。我认为以迭代方式使用 JSON.stringify 和 try catch 块可能也是一种方法。但我不确定它会 more/less 性能。

Answer 1

您可以采用检查循环性质的函数并存储访问过的节点以防止永远循环。

结果是一个具有起始键及其循环节点的对象。想要的格式留给 reader.

作为练习

function isCyclic(node, target, [...visited] = []) {
    if (node === target) return true;
    if (visited.includes(node) || !myMap[node]) return false;
    visited.push(node);
    return myMap[node].some(n => isCyclic(n, target, visited));
}

var myMap = { v1: ['v2', 'v4', 'v5'], v2: ['x', 'v4', 'y'], v3: ['v2', 'v4', 'v5'], v4: ['e', 'v1', 'v5'], v5: ['v2', 'v4', 'v3'] },
    result = {};
   
Object.entries(myMap).forEach(([k, v]) => result[k] = v.filter(n => isCyclic(n, k)));

console.log(result);

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在数组的Map中不使用图查找循环依赖

Find cyclic dependency without using graph in Map of array

javascript

graph

cyclic-graph

cyclic-dependency