Merge pull request youngyangyang04#2680 from nineninee/km0108

添加 卡码网0108.冗余连接 JS版

Author: youngyangyang04

Diff for: problems/kamacoder/0108.冗余连接.md

@@ -141,6 +141,70 @@ int main() {
 
 ### Javascript
 
+```javascript
+const r1 = require('readline').createInterface({ input: process.stdin });
+// 创建readline接口
+let iter = r1[Symbol.asyncIterator]();
+// 创建异步迭代器
+const readline = async () => (await iter.next()).value;
+
+
+let N // 节点数和边数
+let father = []  // 并查集
+
+
+// 并查集初始化
+const init = () => {
+  for (let i = 1; i <= N; i++)  father[i] = i;
+}
+
+// 并查集里寻根的过程
+const find = (u) => {
+  return u == father[u] ? u : father[u] = find(father[u])
+}
+
+// 将v->u 这条边加入并查集
+const join = (u, v) => {
+  u = find(u)
+  v = find(v)
+  if (u == v) return // 如果发现根相同，则说明在一个集合，不用两个节点相连直接返回
+  father[v] = u
+}
+
+// 判断 u 和 v是否找到同一个根
+const isSame = (u, v) => {
+  u = find(u)
+  v = find(v)
+  return u == v
+}
+
+
+(async function () {
+  // 读取第一行输入
+  let line = await readline();
+  N = Number(line);
+
+  // 初始化并查集
+  father = new Array(N)
+  init()
+
+  // 读取边信息, 加入并查集
+  for (let i = 0; i < N; i++) {
+    line = await readline()
+    line = line.split(' ').map(Number)
+
+    if (!isSame(line[0], line[1])) {
+      join(line[0], line[1])
+    }else{
+      console.log(line[0], line[1]);
+      break
+    }
+  }
+})()
+```
+
+
+
 ### TypeScript
 
 ### PhP