feat: solve No.1822

Author: BaffinLee

1801-1900/1822. Sign of the Product of an Array.md

@@ -0,0 +1,83 @@
+# 1822. Sign of the Product of an Array
+
+- Difficulty: Easy.
+- Related Topics: Array, Math.
+- Similar Questions: .
+
+## Problem
+
+There is a function `signFunc(x)` that returns:
+
+
+	
+- `1` if `x` is positive.
+	
+- `-1` if `x` is negative.
+	
+- `0` if `x` is equal to `0`.
+
+
+You are given an integer array `nums`. Let `product` be the product of all values in the array `nums`.
+
+Return `signFunc(product)`.
+
+ 
+Example 1:
+
+```
+Input: nums = [-1,-2,-3,-4,3,2,1]
+Output: 1
+Explanation: The product of all values in the array is 144, and signFunc(144) = 1
+```
+
+Example 2:
+
+```
+Input: nums = [1,5,0,2,-3]
+Output: 0
+Explanation: The product of all values in the array is 0, and signFunc(0) = 0
+```
+
+Example 3:
+
+```
+Input: nums = [-1,1,-1,1,-1]
+Output: -1
+Explanation: The product of all values in the array is -1, and signFunc(-1) = -1
+```
+
+ 
+**Constraints:**
+
+
+	
+- `1 <= nums.length <= 1000`
+	
+- `-100 <= nums[i] <= 100`
+
+
+
+## Solution
+
+```javascript
+/**
+ * @param {number[]} nums
+ * @return {number}
+ */
+var arraySign = function(nums) {
+    var res = 1;
+    for (var i = 0; i < nums.length; i++) {
+        res *= nums[i] > 0 ? 1 : (nums[i] === 0 ? 0 : -1);
+    }
+    return res;
+};
+```
+
+**Explain:**
+
+nope.
+
+**Complexity:**
+
+* Time complexity : O(n).
+* Space complexity : O(n).