feat: add kotlin solution to lc problem: No.0304

Author: Zuoqiu-Yingyi

solution/0300-0399/0304.Range Sum Query 2D - Immutable/README.md

@@ -39,10 +39,10 @@ tags:
 <p><img src="https://fastly.jsdelivr.net/gh/doocs/leetcode@main/solution/0300-0399/0304.Range%20Sum%20Query%202D%20-%20Immutable/images/1626332422-wUpUHT-image.png" style="width: 200px;" /></p>
 
 <pre>
-<strong>输入:</strong> 
+<strong>输入:</strong>
 ["NumMatrix","sumRegion","sumRegion","sumRegion"]
 [[[[3,0,1,4,2],[5,6,3,2,1],[1,2,0,1,5],[4,1,0,1,7],[1,0,3,0,5]]],[2,1,4,3],[1,1,2,2],[1,2,2,4]]
-<strong>输出:</strong> 
+<strong>输出:</strong>
 [null, 8, 11, 12]
 
 <strong>解释:</strong>
@@ -347,6 +347,56 @@ NumMatrix.prototype.sumRegion = function (row1, col1, row2, col2) {
  */
 ```
 
+#### Kotlin
+
+```kotlin
+class NumMatrix(matrix: Array<IntArray>) {
+    private val n: Int
+    private val m: Int
+    private val matrix: Array<IntArray>
+    private val prefix_sums_matrix: Array<IntArray>
+    private var initialized: Boolean
+
+    init {
+        this.n = matrix.size
+        this.m = matrix[0].size
+        this.matrix = matrix
+        this.prefix_sums_matrix = Array(n + 1) { IntArray(m + 1) }
+        this.initialized = false
+    }
+
+    fun sumRegion(row1: Int, col1: Int, row2: Int, col2: Int): Int {
+        this.init()
+        return this.prefix_sums_matrix[row2 + 1][col2 + 1] -
+            this.prefix_sums_matrix[row2 + 1][col1] -
+            this.prefix_sums_matrix[row1][col2 + 1] +
+            this.prefix_sums_matrix[row1][col1]
+    }
+
+    private fun init(): Boolean {
+        if (!this.initialized) {
+            for (i in 0..<this.n) {
+                for (j in 0..<this.m) {
+                    this.prefix_sums_matrix[i + 1][j + 1] =
+                        this.prefix_sums_matrix[i + 1][j] +
+                        this.prefix_sums_matrix[i][j + 1] -
+                        this.prefix_sums_matrix[i][j] +
+                        this.matrix[i][j]
+                }
+            }
+            this.initialized = true
+            return true
+        }
+        return false
+    }
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such: var obj = NumMatrix(matrix) var
+ * param_1 = obj.sumRegion(row1,col1,row2,col2)
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0300-0399/0304.Range Sum Query 2D - Immutable/README_EN.md

@@ -346,6 +346,56 @@ NumMatrix.prototype.sumRegion = function (row1, col1, row2, col2) {
  */
 ```
 
+#### Kotlin
+
+```kotlin
+class NumMatrix(matrix: Array<IntArray>) {
+    private val n: Int
+    private val m: Int
+    private val matrix: Array<IntArray>
+    private val prefix_sums_matrix: Array<IntArray>
+    private var initialized: Boolean
+
+    init {
+        this.n = matrix.size
+        this.m = matrix[0].size
+        this.matrix = matrix
+        this.prefix_sums_matrix = Array(n + 1) { IntArray(m + 1) }
+        this.initialized = false
+    }
+
+    fun sumRegion(row1: Int, col1: Int, row2: Int, col2: Int): Int {
+        this.init()
+        return this.prefix_sums_matrix[row2 + 1][col2 + 1] -
+            this.prefix_sums_matrix[row2 + 1][col1] -
+            this.prefix_sums_matrix[row1][col2 + 1] +
+            this.prefix_sums_matrix[row1][col1]
+    }
+
+    private fun init(): Boolean {
+        if (!this.initialized) {
+            for (i in 0..<this.n) {
+                for (j in 0..<this.m) {
+                    this.prefix_sums_matrix[i + 1][j + 1] =
+                        this.prefix_sums_matrix[i + 1][j] +
+                        this.prefix_sums_matrix[i][j + 1] -
+                        this.prefix_sums_matrix[i][j] +
+                        this.matrix[i][j]
+                }
+            }
+            this.initialized = true
+            return true
+        }
+        return false
+    }
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such: var obj = NumMatrix(matrix) var
+ * param_1 = obj.sumRegion(row1,col1,row2,col2)
+ */
+```
+
 <!-- tabs:end -->
 
 <!-- solution:end -->

solution/0300-0399/0304.Range Sum Query 2D - Immutable/Solution.kt

@@ -0,0 +1,45 @@
+class NumMatrix(matrix: Array<IntArray>) {
+    private val n: Int
+    private val m: Int
+    private val matrix: Array<IntArray>
+    private val prefix_sums_matrix: Array<IntArray>
+    private var initialized: Boolean
+
+    init {
+        this.n = matrix.size
+        this.m = matrix[0].size
+        this.matrix = matrix
+        this.prefix_sums_matrix = Array(n + 1) { IntArray(m + 1) }
+        this.initialized = false
+    }
+
+    fun sumRegion(row1: Int, col1: Int, row2: Int, col2: Int): Int {
+        this.init()
+        return this.prefix_sums_matrix[row2 + 1][col2 + 1] -
+            this.prefix_sums_matrix[row2 + 1][col1] -
+            this.prefix_sums_matrix[row1][col2 + 1] +
+            this.prefix_sums_matrix[row1][col1]
+    }
+
+    private fun init(): Boolean {
+        if (!this.initialized) {
+            for (i in 0..<this.n) {
+                for (j in 0..<this.m) {
+                    this.prefix_sums_matrix[i + 1][j + 1] =
+                        this.prefix_sums_matrix[i + 1][j] +
+                        this.prefix_sums_matrix[i][j + 1] -
+                        this.prefix_sums_matrix[i][j] +
+                        this.matrix[i][j]
+                }
+            }
+            this.initialized = true
+            return true
+        }
+        return false
+    }
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such: var obj = NumMatrix(matrix) var
+ * param_1 = obj.sumRegion(row1,col1,row2,col2)
+ */