updated problems.

src/subStringsKDist.js

@@ -0,0 +1,30 @@
+function areDistinctChars(chars) {
+  const charCache = {};
+
+  for (let i = 0; i < chars.length; i++) {
+    if (charCache[chars[i]] !== undefined) {
+      return false;
+    } else {
+      charCache[chars[i]] = 0;
+    }
+  }
+  return true;
+}
+
+function subStringsKDist(inputStr, kDistinctLettters) {
+  const chars = inputStr.split("");
+  const subStrings = {};
+
+  for (let i = 0; i < chars.length; i++) {
+    const subArray = chars.slice(i, i + kDistinctLettters);
+    if (subArray.length === kDistinctLettters) {
+      if (areDistinctChars(subArray)) {
+        subStr = subArray.join("");
+        if (subStrings[subStr] === undefined) {
+          subStrings[subStr] = 0;
+        }
+      }
+    }
+  }
+  return Object.keys(subStrings);
+}