diff --git a/contains-duplicate/casentino.ts b/contains-duplicate/casentino.ts
new file mode 100644
index 000000000..fe800d220
--- /dev/null
+++ b/contains-duplicate/casentino.ts
@@ -0,0 +1,4 @@
+function containsDuplicate(nums: number[]): boolean {
+  const duplicateSet = new Set(nums);
+  return duplicateSet.size !== nums.length;
+}
diff --git a/longest-consecutive-sequence/casentino.ts b/longest-consecutive-sequence/casentino.ts
new file mode 100644
index 000000000..0d027c2b1
--- /dev/null
+++ b/longest-consecutive-sequence/casentino.ts
@@ -0,0 +1,20 @@
+function longestConsecutive(nums: number[]): number {
+  if (nums.length === 0) {
+    return 0;
+  }
+
+  const smallest = nums.sort((a, b) => a - b);
+  let longest = 1;
+  let sequence = 1;
+  for (let i = 1; i < smallest.length; i++) {
+    if (smallest[i] - smallest[i - 1] === 1) {
+      sequence += 1;
+    } else if (smallest[i] !== smallest[i - 1]) {
+      sequence = 1;
+    }
+    if (longest < sequence) {
+      longest = sequence;
+    }
+  }
+  return longest;
+}
diff --git a/top-k-frequent-elements/casentino.ts b/top-k-frequent-elements/casentino.ts
new file mode 100644
index 000000000..5f9dc8d40
--- /dev/null
+++ b/top-k-frequent-elements/casentino.ts
@@ -0,0 +1,16 @@
+function topKFrequent(nums: number[], k: number): number[] {
+  const numsMap = new Map<number, number>();
+  for (let i = 0; i < nums.length; i++) {
+    if (numsMap.has(nums[i])) {
+      numsMap.set(nums[i], (numsMap.get(nums[i]) ?? 0) + 1);
+    } else {
+      numsMap.set(nums[i], 1);
+    }
+  }
+  const sortedNums = Array.from(numsMap).sort(([_a, a], [_b, b]) => b - a);
+  const results: number[] = [];
+  for (let j = 0; j < sortedNums.length && results.length < k; j++) {
+    results.push(sortedNums[j][0]);
+  }
+  return results;
+}
diff --git a/two-sum/casentino.ts b/two-sum/casentino.ts
new file mode 100644
index 000000000..1e15a3845
--- /dev/null
+++ b/two-sum/casentino.ts
@@ -0,0 +1,9 @@
+function twoSum(nums: number[], target: number): number[] | undefined {
+  for (let i = 0; i < nums.length; i++) {
+    for (let j = i + 1; j < nums.length; j++) {
+      if (nums[i] + nums[j] === target) {
+        return [i, j];
+      }
+    }
+  }
+}