add: product of array except self solution

Author: JEONGBEOMKO

product-of-array-except-self/JEONGBEOMKO.java

@@ -0,0 +1,27 @@
+/* [time-complexity]: O(n)
+   [space-complexity]: O(1)
+ */
+public class JEONGBEOMKO {
+
+    class Solution {
+        public int[] productExceptSelf(int[] nums) {
+            int n = nums.length;
+            int[] result = new int[n];
+
+            // 왼쪽 곱 계산
+            result[0] = 1;
+            for (int i = 1; i < n; i++) {
+                result[i] = result[i - 1] * nums[i - 1];
+            }
+
+            // 오른쪽 곱과 동시에 결과 계산
+            int rightProduct = 1;
+            for (int i = n - 1; i >= 0; i--) {
+                result[i] = result[i] * rightProduct;
+                rightProduct *= nums[i];
+            }
+
+            return result;
+        }
+    }
+}