3Sum

Author: casentino

3sum/casentino.ts

@@ -0,0 +1,34 @@
+function threeSum(nums: number[]): number[][] {
+  const sortedNums = nums.sort((a, b) => a - b);
+  const results: number[][] = [];
+  for (let i = 0; i < sortedNums.length - 2; i++) {
+    const current = sortedNums[i];
+    if (current > 0) {
+      return results;
+    }
+    if (i > 0 && current === sortedNums[i - 1]) {
+      continue;
+    }
+    let left = i + 1;
+    let right = sortedNums.length - 1;
+    while (left < right) {
+      const sum = current + sortedNums[left] + sortedNums[right];
+      if (sum > 0) {
+        right -= 1;
+      } else if (sum < 0) {
+        left += 1;
+      } else {
+        results.push([current, sortedNums[left], sortedNums[right]]);
+        left += 1;
+        right -= 1;
+        while (left < right && sortedNums[left] === sortedNums[left - 1]) {
+          left += 1;
+        }
+        while (left < right && sortedNums[right] === sortedNums[right + 1]) {
+          right -= 1;
+        }
+      }
+    }
+  }
+  return results;
+}