Added best time solution

Author: nhistory

best-time-to-buy-and-sell-stock/nhistory.js

@@ -0,0 +1,30 @@
+/**
+ * @param {number[]} prices
+ * @return {number}
+ */
+var maxProfit = function (prices) {
+  // Initiate left and right pointer (left: buy price / right: sell price)
+  // Make profit with initiative value 0
+  let l = 0;
+  let r = 1;
+  let profit = 0;
+  // Iterate to check profit = prices[r] - prices[l]
+  while (r < prices.length) {
+    // If profit is positive, compare profit with previous one
+    if (prices[r] > prices[l]) {
+      profit = Math.max(profit, prices[r] - prices[l]);
+      r++;
+    } else {
+      // If profit is negative, move forware left and right pointer
+      l = r;
+      r++;
+    }
+  }
+  return profit;
+};
+
+// TC: O(n)
+// SC: O(3)
+
+console.log(maxProfit([7, 1, 5, 3, 6, 4])); //5
+console.log(maxProfit([7, 6, 4, 3, 1])); //0

valid-anagram/nhistory.js

@@ -18,8 +18,10 @@ var isAnagram = function (s, t) {
   if (s.length !== t.length) return false;
   // Put a character and add or substract number
   for (let i = 0; i < s.length; i++) {
-    map[s[i]] = map[s[i]] ? map[s[i]] + 1 : 1;
-    map[t[i]] = map[t[i]] ? map[t[i]] - 1 : -1;
+    // map[s[i]] = map[s[i]] ? map[s[i]] + 1 : 1;
+    map[s[i]] = (map[s[i]] ?? 0) + 1;
+    // map[t[i]] = map[t[i]] ? map[t[i]] - 1 : -1;
+    map[t[i]] = (map[t[i]] ?? 0) - 1;
   }
 
   for (let i = 0; i < s.length; i++) {