[RiaOh] WEEK 02 solutions

climbing-stairs/RiaOh.js

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+/**
+ * @param {number} n
+ * @return {number}
+ */
+var climbStairs = function (n) {
+  const arr = [1, 2];
+  for (let i = 2; i <= n - 1; i++) {
+    arr[i] = arr[i - 2] + arr[i - 1];
+  }
+  return arr[n - 1];
+};

number-of-1-bits/RiaOh.js

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+/**
+ * @param {number} n
+ * @return {number}
+ */
+var hammingWeight = function (n) {
+  const binary = n.toString(2);
+  const arr = [...binary];
+  let count = 0;
+  arr.map((num) => {
+    if (num === "1") {
+      count++;
+    }
+  });
+  return count;
+};

product-of-array-except-self/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @return {number[]}
+ */
+var productExceptSelf = function (nums) {
+  // [-1,1,0,-3,3]
+  if (!nums.includes(0)) {
+    const allNumsProduct = nums.reduce((acc, cur) => acc * cur);
+    return nums.map((num) => allNumsProduct / num);
+  } else {
+    let arr = [];
+    for (let i = 0; i < nums.length; i++) {
+      if (nums[i] !== 0) {
+        arr[i] = 0;
+      } else {
+        console.log("여기는?");
+        const newArr = [...nums];
+        newArr.splice(i, 1);
+        console.log("newArr ==>", newArr);
+        if (newArr.includes(0)) {
+          arr[i] = 0;
+        } else {
+          const product = newArr.reduce((arr, cur) => arr * cur);
+          console.log("product ==>", product);
+          arr[i] = product;
+        }
+      }
+    }
+    return arr;
+  }
+};

valid-anagram/RiaOh.js

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+/**
+ * @param {string} s
+ * @param {string} t
+ * @return {boolean}
+ */
+var isAnagram = function (s, t) {
+  let resultS = [...s].sort();
+  let resultT = [...t].sort();
+  return resultS.join() === resultT.join();
+};

valid-palindrome/RiaOh.js

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+/**
+ * @param {string} s
+ * @return {boolean}
+ */
+var isPalindrome = function (s) {
+  const arr = [...s];
+  let text = "";
+  for (let i = 0; i < arr.length; i++) {
+    if (isAlphabet(arr[i]) === true && arr[i] !== " ") {
+      text = text + arr[i].toLowerCase();
+    } else if (isNumeric(arr[i]) === true && arr[i] !== " ") {
+      text = text + arr[i];
+    }
+  }
+  console.log("text -->", text);
+  for (let i = 0; i < text.length / 2; i++) {
+    if (text[i] !== text[text.length - 1 - i]) {
+      return false;
+    }
+  }
+  return true;
+};
+
+function isAlphabet(char) {
+  return /[a-zA-Z]/.test(char);
+}
+
+function isNumeric(str) {
+  return !isNaN(str);
+}