[RiaOh] WEEK 01 solutions

contains-duplicate/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @return {boolean}
+ */
+var containsDuplicate = function (nums) {
+  let count = [nums[0]];
+  for (let i = 1; i < nums.length; i++) {
+    if (count.includes(nums[i])) {
+      return true;
+    } else {
+      count.push(nums[i]);
+    }
+  }
+  return false;
+};

house-robber/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var rob = function (nums) {
+  if (nums.length <= 1) {
+    if (nums.length === 0) {
+      return 0;
+    } else {
+      return nums[0];
+    }
+  }
+
+  const arr = new Array(nums.length + 1);
+  arr[0] = 0;
+  arr[1] = nums[0];
+  for (let i = 2; i < arr.length; i++) {
+    arr[i] = Math.max(arr[i - 1], arr[i - 2] + nums[i - 1]);
+  }
+  return arr[arr.length - 1];
+};

longest-consecutive-sequence/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var longestConsecutive = function (nums) {
+  if (nums.length === 0) {
+    return 0;
+  }
+  const set = new Set(nums);
+  const uniquiArr = [...set];
+  uniquiArr.sort((a, b) => a - b);
+  const lengthArr = [1];
+  for (let i = 1; i < uniquiArr.length; i++) {
+    if (uniquiArr[i - 1] + 1 === uniquiArr[i]) {
+      const last = lengthArr[lengthArr.length - 1] + 1;
+      lengthArr.pop();
+      lengthArr.push(last);
+    } else {
+      lengthArr.push(1);
+    }
+  }
+  return Math.max.apply(null, lengthArr);
+};

top-k-frequent-elements/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @param {number} k
+ * @return {number[]}
+ */
+var topKFrequent = function (nums, k) {
+  const obj = {};
+  for (let i = 0; i < nums.length; i++) {
+    if (Object.keys(obj).includes(String(nums[i]))) {
+      obj[nums[i]] = obj[nums[i]] + 1;
+    } else {
+      obj[nums[i]] = 1;
+    }
+  }
+
+  const keysArr = Object.keys(obj);
+  const sortedObj = keysArr
+    .sort((a, b) => obj[b] - obj[a])
+    .slice(0, k)
+    .map((num) => Number(num));
+  return sortedObj;
+};

two-sum/RiaOh.js

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+/**
+ * @param {number[]} nums
+ * @param {number} target
+ * @return {number[]}
+ */
+var twoSum = function (nums, target) {
+  let result = [];
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        result = [i, j];
+      }
+    }
+  }
+  return result;
+};