Add: Exercise 283. Move Zeroes

Author: BlackBeast593

283-move-zeroes/README.md

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+# 283. Move Zeroes
+Given an integer array `nums`, move all 0's to the end of it while maintaining the relative order of
+the non-zero elements.
+
+Note that you must do this in-place without making a copy of the array.
+
+## Examples
+
+### Example 1:
+Input: `nums` = [0,1,0,3,12]
+Output: [1,3,12,0,0]
+
+### Example 2:
+Input: `nums` = [0]
+Output: [0]
+
+## Constraints
+- 1 <= `nums.length` <= 10^4
+- -2^31 <= `nums[i]` <= 2^31 - 1

283-move-zeroes/index.js

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+/**
+ * Shifts all zeroes in `nums` to the end while keeping other elements in order.
+ * Uses `left` and `right` pointers to swap zeroes with non-zero elements.
+ * Example: [1,4,0,0,5] -> left = 2, right = 4. Swap nums[4] with nums[2].
+ * Result: [1,4,5,0,0]
+ * @param {number[]} nums
+ * @return {void} Do not return anything, modify nums in-place instead.
+ */
+var moveZeroes = function(nums) {
+    let i = 0 // Will traverse the nums array
+    let left = null // left limit of zeroes window
+    let right = null // right limit of zeroes window
+
+    const n = nums.length
+
+    while (i < n && right < n) {
+        if (nums[i] === 0) {
+            // Initialize left and right when zero is found for the first time
+            if (left === null) {
+                left = i
+                if (right === null) {
+                    right = left + 1
+                }
+                i++
+                continue
+            }
+            i++
+            right++
+            continue
+        }
+
+        // Continue looking for a zero
+        if (left === null && right === null) {
+            i++
+            continue
+        }
+
+        // Swap num with the zero at the left
+        [nums[i], nums[left]] = [nums[left], nums[i]]
+        
+        left++
+        right++
+        i = right
+    }
+};
+
+module.exports = moveZeroes

283-move-zeroes/package.json

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+{
+  "name": "283-move-zeroes",
+  "version": "1.0.0",
+  "description": "Given an integer array `nums`, move all 0's to the end of it while maintaining the relative order of the non-zero elements.",
+  "main": "index.js",
+  "scripts": {
+    "start": "node index.js",
+    "debug": "node --inspect-brk index.js",
+    "test": "node test.js"
+  },
+  "keywords": [],
+  "author": "",
+  "license": "ISC"
+}

283-move-zeroes/test.js

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+const assert = require('assert')
+const moveZeroes = require('./index')
+
+const tt = [
+    {
+        nums: [0,1,0,3,12],
+        expected: [1,3,12,0,0,]
+    },
+    {
+        nums: [0],
+        expected: [0]
+    },
+    {
+        nums: [0,1],
+        expected: [1,0]
+    }
+]
+
+for (const t of tt) {
+    moveZeroes(t.nums)
+    assert.strict.deepEqual(t.nums, t.expected)
+}

README.md

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+# Leetcode 75 Notes
+
+## `package.json` scripts
+```json
+{
+  // ...
+  "scripts": {
+    "start": "node index.js",
+    "debug": "node --inspect-brk index.js",
+    "test": "node test.js"
+  },
+  // ...
+}
+
+```