[gitsunmin] Week 5 Solutions

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

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+/**
+ * https://leetcode.com/problems/best-time-to-buy-and-sell-stock
+ * time complexity : O(n)
+ * space complexity : O(1)
+ */
+
+function maxProfit(prices: number[]): number {
+    let maxProfit = 0;
+    let [minPrice] = prices;
+
+    for (let price of prices) {
+        maxProfit = Math.max(maxProfit, price - minPrice);
+        minPrice = Math.min(minPrice, price);
+    }
+
+    return maxProfit;
+};

group-anagrams/gitsunmin.ts

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+/**
+ * https://leetcode.com/problems/group-anagrams
+ * time complexity : O(n * k log k)
+ * space complexity : O(n * k)
+ */
+function groupAnagrams(strs: string[]): string[][] {
+    const map = new Map();
+
+    for (const str of strs) {
+        const sortedStr = str.split("").sort().join("");
+
+        if (map.has(sortedStr)) map.get(sortedStr).push(str);
+        else map.set(sortedStr, [str]);
+    }
+
+    return Array.from(map.values());
+};