resolve #134-common-child 문제풀이 및 문서추가

Interview-Preparation-Kit/String-Manipulation/common-child.js

@@ -0,0 +1,35 @@
+/**
+ * @title Common Child
+ * @difficulty Medium
+ * @link https://www.hackerrank.com/challenges/common-child/problem
+ */
+
+const lca = (string1, string2) => {
+  const s1 = (string1.length <= string2.length) ? [...string1] : [...string2];
+  const s2 = (string1.length <= string2.length) ? [...string2] : [...string1];
+  const {length: rowLength} = s1;
+  const {length: colLength} = s2;
+  let row = s1.reduce(acc => {
+    acc.push(0);
+
+    return acc;
+  }, []);
+  row.push(0);
+
+  const cur = [...row];
+
+  for (let idxS2 = 0; idxS2 < colLength; idxS2++) {
+    for (let idxS1 = 0; idxS1 < rowLength; idxS1++) {
+      if (s1[idxS1] === s2[idxS2]) {
+        cur[idxS1 + 1] = row[idxS1] + 1;
+      } else {
+        cur[idxS1 + 1] = (Math.max(cur[idxS1], row[idxS1 + 1]));
+      }
+    }
+    row = [...cur];
+  }
+
+  return cur[rowLength];
+};
+
+const commonChild = (s1, s2) => lca(s1, s2);

README.md

@@ -64,6 +64,13 @@ Generates the README.md.
 | --- | --- | --- |
 | Easy | [2D Array - DS](https://www.hackerrank.com/challenges/2d-array/problem) | [Solution](./Interview-Preparation-Kit/Arrays/2d-array-ds.js)|
 | Easy | [Left Rotation](https://www.hackerrank.com/challenges/ctci-array-left-rotation/problem) | [Solution](./Interview-Preparation-Kit/Arrays/left-rotation.js)|
+#### String-Manipulation
+| Difficulty | Problem | Solution |
+| --- | --- | --- |
+| Medium | [Common Child](https://www.hackerrank.com/challenges/common-child/problem) | [Solution](./Interview-Preparation-Kit/String-Manipulation/common-child.js)|
+#### Strings
+| Difficulty | Problem | Solution |
+| --- | --- | --- |
 #### Warm-up-Challenges
 | Difficulty | Problem | Solution |
 | --- | --- | --- |