From d925ef998de5aeb1ad829bc95014c0b0f3b5c4e3 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=D0=A2=D0=B8=D1=89=D0=B5=D0=BD=D0=BA=D0=BE=20=D0=9A=D0=BE?=
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 <ktischenko@dev.vtb.ru>
Date: Wed, 29 Jun 2022 00:14:03 +0300
Subject: [PATCH] 303. Range Sum Query - Immutable

---
 DP/RangeSumQueryImmutable.swift | 27 +++++++++++++++++++++++++++
 1 file changed, 27 insertions(+)
 create mode 100644 DP/RangeSumQueryImmutable.swift

diff --git a/DP/RangeSumQueryImmutable.swift b/DP/RangeSumQueryImmutable.swift
new file mode 100644
index 00000000..989c054e
--- /dev/null
+++ b/DP/RangeSumQueryImmutable.swift
@@ -0,0 +1,27 @@
+/**
+ * Question Link: https://leetcode.com/problems/range-sum-query-immutable/
+ * Primary idea: Calculate the sum of the elements of nums between indices left and right
+ * Time Complexity: O(n), Space Complexity: O(1)
+ *
+ */
+
+class NumArray {
+	var sums: [Int] = []
+
+	init(_ nums: [Int]) {
+		var currentSum = 0
+
+		for num in nums {
+			currentSum += num
+			sums.append(currentSum)
+		}
+		print(sums)
+	}
+
+	func sumRange(_ left: Int, _ right: Int) -> Int {
+		if left == 0 {
+			return sums[right]
+		}
+		return sums[right] - sums[left-1]
+	}
+}