Merge pull request DaleStudy#41 from sounmind/main

[Evan] Week 1 Assignment Submission

Author: DaleSeo

best-time-to-buy-and-sell-stock/sounmind.ts

@@ -0,0 +1,18 @@
+function maxProfit(prices: number[]): number {
+  let minPrice = Number.MAX_SAFE_INTEGER;
+  let maxProfit = 0;
+
+  for (let i = 0; i < prices.length; i++) {
+    if (prices[i] < minPrice) {
+      minPrice = prices[i];
+    }
+
+    const potentialProfit = prices[i] - minPrice;
+
+    if (maxProfit < potentialProfit) {
+      maxProfit = potentialProfit;
+    }
+  }
+
+  return maxProfit;
+}

contains-duplicate/sounmind.ts

@@ -0,0 +1,3 @@
+function containsDuplicate(nums: number[]): boolean {
+  return nums.length !== new Set(nums).size;
+}

two-sum/sounmind.ts

@@ -0,0 +1,24 @@
+function twoSum(nums: number[], target: number): number[] {
+  // Pair each element with its index
+  const numsWithIndex = nums.map((value, index) => ({ value, index }));
+
+  // Sort the array based on the values
+  numsWithIndex.sort((a, b) => a.value - b.value);
+
+  let left = 0;
+  let right = numsWithIndex.length - 1;
+
+  while (left < right) {
+    const sum = numsWithIndex[left].value + numsWithIndex[right].value;
+
+    if (sum === target) {
+      return [numsWithIndex[left].index, numsWithIndex[right].index];
+    } else if (sum < target) {
+      left++;
+    } else {
+      right--;
+    }
+  }
+
+  return []; // In case there is no solution
+}

valid-anagram/sounmind.ts

@@ -0,0 +1,25 @@
+function isAnagram(s: string, t: string): boolean {
+  if (s.length !== t.length) {
+    return false;
+  }
+
+  const frequencyMap = {};
+
+  for (const letter of s) {
+    if (frequencyMap[letter]) {
+      frequencyMap[letter] += 1;
+    } else {
+      frequencyMap[letter] = 1;
+    }
+  }
+
+  for (const letter of t) {
+    if (frequencyMap[letter]) {
+      frequencyMap[letter] -= 1;
+    } else {
+      return false;
+    }
+  }
+
+  return true;
+}

valid-palindrome/sounmind.ts

@@ -0,0 +1,16 @@
+function isPalindrome(s: string): boolean {
+  const filteredString = s.replace(/[^a-zA-Z0-9]/g, "").toUpperCase();
+
+  let [left, right] = [0, filteredString.length - 1];
+
+  while (left <= right) {
+    if (filteredString[left] !== filteredString[right]) {
+      return false;
+    }
+
+    left += 1;
+    right -= 1;
+  }
+
+  return true;
+}