Create 2103-rings-and-rods.js

Author: everthis

2103-rings-and-rods.js

@@ -0,0 +1,22 @@
+/**
+ * @param {string} rings
+ * @return {number}
+ */
+const countPoints = function(rings) {
+  const hash = {}
+  
+  for(let i = 0, n = rings.length; i < n; i+=2) {
+    const ch = rings[i], num = +rings[i + 1]
+    if(hash[num] == null) hash[num] = new Set()
+    hash[num].add(ch)
+  }
+  
+  
+  
+  let res = 0
+  Object.keys(hash).forEach(k => {
+    if(hash[k].size === 3) res++
+  })
+  
+  return res
+};