solve: 3sum

Author: sounmind

3sum/evan.js

@@ -0,0 +1,49 @@
+/**
+ * @param {number[]} nums
+ * @return {number[][]}
+ */
+var threeSum = function (nums) {
+  const sorted = nums.sort((a, b) => a - b);
+  const result = [];
+
+  for (let i = 0; i < sorted.length; i++) {
+    const fixedNumber = sorted[i];
+    const previousFixedNumber = sorted[i - 1];
+
+    if (fixedNumber === previousFixedNumber) {
+      continue;
+    }
+
+    let [leftEnd, rightEnd] = [i + 1, sorted.length - 1];
+
+    while (leftEnd < rightEnd) {
+      const sum = fixedNumber + sorted[leftEnd] + sorted[rightEnd];
+
+      if (sum === 0) {
+        result.push([sorted[leftEnd], sorted[rightEnd], sorted[i]]);
+
+        while (
+          sorted[leftEnd + 1] === sorted[leftEnd] ||
+          sorted[rightEnd - 1] === sorted[rightEnd]
+        ) {
+          if (sorted[leftEnd + 1] === sorted[leftEnd]) {
+            leftEnd += 1;
+          }
+
+          if (sorted[rightEnd - 1] === sorted[rightEnd]) {
+            rightEnd -= 1;
+          }
+        }
+
+        leftEnd += 1;
+        rightEnd -= 1;
+      } else if (sum < 0) {
+        leftEnd += 1;
+      } else {
+        rightEnd -= 1;
+      }
+    }
+  }
+
+  return result;
+};