ts-2: longest_chain

Author: aikhelis

typescript/Hash Maps and Sets/longest_chain_of_consecutive_numbers.ts

@@ -0,0 +1,21 @@
+function longest_chain_of_consecutive_numbers(nums: number[]): number {
+    if (nums.length === 0)
+        return 0;
+    const num_set = new Set(nums);
+    let longest_chain = 0;
+    for (const num of num_set) {
+        // If the current number is the smallest number in its chain, search for
+        // the length of its chain.
+        if (!num_set.has(num - 1)) {
+            let currentNum = num;
+            let currentChain = 1;
+            // Continue to find the next consecutive numbers in the chain.
+            while (num_set.has(currentNum + 1)) {
+                currentNum += 1;
+                currentChain += 1;
+            }
+            longest_chain = Math.max(longest_chain, currentChain);
+        }
+    }
+    return longest_chain;
+}

typescript/Hash Maps and Sets/longest_chain_of_consecutive_numbers_brute_force.ts

@@ -0,0 +1,17 @@
+function longest_chain_of_consecutive_numbers_brute_force(nums: number[]): number {
+    if (nums.length === 0)
+        return 0;
+    let longest_chain = 0;
+    // Look for chains of consecutive numbers that start from each number.
+    for (const num of nums) {
+        let current_num = num;
+        let current_chain = 1;
+        // Continue to find the next consecutive numbers in the chain.
+        while (nums.includes(current_num + 1)) {
+            current_num += 1;
+            current_chain += 1;
+        }
+        longest_chain = Math.max(longest_chain, current_chain);
+    }
+    return longest_chain;
+}