feat: add solutions to lc problem: No.0304. Range Sum Query 2D - Immutable

Author: yanglbme

README.md

@@ -188,6 +188,7 @@
 - [下降路径最小和](./solution/0900-0999/0931.Minimum%20Falling%20Path%20Sum/README.md)
 - [三角形最小路径和](./solution/0100-0199/0120.Triangle/README.md)
 - [矩阵区域和](./solution/1300-1399/1314.Matrix%20Block%20Sum/README.md)
+- [二维区域和检索 - 矩阵不可变](./solution/0300-0399/0304.Range%20Sum%20Query%202D%20-%20Immutable/README.md)
 - [礼物的最大价值](./lcof/面试题47.%20礼物的最大价值/README.md)
 - [最小路径和](./solution/0000-0099/0064.Minimum%20Path%20Sum/README.md)
 - [最长上升子序列](./solution/0300-0399/0300.Longest%20Increasing%20Subsequence/README.md)

README_EN.md

@@ -182,6 +182,7 @@ Complete solutions to [LeetCode](https://leetcode.com/problemset/all/), [LCOF](h
 - [Minimum Falling Path Sum](./solution/0900-0999/0931.Minimum%20Falling%20Path%20Sum/README_EN.md)
 - [Triangle](./solution/0100-0199/0120.Triangle/README_EN.md)
 - [Matrix Block Sum](./solution/1300-1399/1314.Matrix%20Block%20Sum/README_EN.md)
+- [Range Sum Query 2D - Immutable](./solution/0300-0399/0304.Range%20Sum%20Query%202D%20-%20Immutable/README_EN.md)
 - [Minimum Path Sum](./solution/0000-0099/0064.Minimum%20Path%20Sum/README_EN.md)
 - [Longest Increasing Subsequence](./solution/0300-0399/0300.Longest%20Increasing%20Subsequence/README_EN.md)
 - [Russian Doll Envelopes](./solution/0300-0399/0354.Russian%20Doll%20Envelopes/README_EN.md)

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

@@ -44,6 +44,8 @@ sumRegion(1, 2, 2, 4) -> 12
 
 <!-- 这里可写通用的实现逻辑 -->
 
+动态规划-二维前缀和。
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -54,17 +56,14 @@ sumRegion(1, 2, 2, 4) -> 12
 class NumMatrix:
 
     def __init__(self, matrix: List[List[int]]):
-        m = len(matrix)
-        if m > 0:
-            n = len(matrix[0])
-            self.sums = [[0] * (n + 1) for _ in range(m + 1)]
-            for i in range(m):
-                for j in range(n):
-                    self.sums[i + 1][j + 1] = self.sums[i][j + 1] + \
-                        self.sums[i + 1][j] - self.sums[i][j] + matrix[i][j]
+        m, n = len(matrix), len(matrix[0])
+        self.pre = [[0] * (n + 1) for _ in range(m + 1)]
+        for i in range(1, m + 1):
+            for j in range(1, n + 1):
+                self.pre[i][j] = self.pre[i - 1][j] + self.pre[i][j - 1] - self.pre[i - 1][j - 1] + matrix[i - 1][j - 1]
 
     def sumRegion(self, row1: int, col1: int, row2: int, col2: int) -> int:
-        return self.sums[row2 + 1][col2 + 1] - self.sums[row2 + 1][col1] - self.sums[row1][col2 + 1] + self.sums[row1][col1]
+        return self.pre[row2 + 1][col2 + 1] - self.pre[row2 + 1][col1] - self.pre[row1][col2 + 1] + self.pre[row1][col1]
 
 
 # Your NumMatrix object will be instantiated and called as such:
@@ -78,23 +77,20 @@ class NumMatrix:
 
 ```java
 class NumMatrix {
-    private int[][] sums;
+    private int[][] pre;
 
     public NumMatrix(int[][] matrix) {
-        int m = matrix.length;
-        if (m > 0) {
-            int n = matrix[0].length;
-            sums = new int[m + 1][n + 1];
-            for (int i = 0; i < m; ++i) {
-                for (int j = 0; j < n; ++j) {
-                    sums[i + 1][j + 1] = sums[i][j + 1] + sums[i + 1][j] - sums[i][j] + matrix[i][j];
-                }
+        int m = matrix.length, n = matrix[0].length;
+        pre = new int[m + 1][n + 1];
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
             }
         }
     }
-
+    
     public int sumRegion(int row1, int col1, int row2, int col2) {
-        return sums[row2 + 1][col2 + 1] - sums[row2 + 1][col1] - sums[row1][col2 + 1] + sums[row1][col1];
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
     }
 }
 
@@ -105,6 +101,67 @@ class NumMatrix {
  */
 ```
 
+### **C++**
+
+```cpp
+class NumMatrix {
+public:
+    vector<vector<int>> pre;
+
+    NumMatrix(vector<vector<int>>& matrix) {
+        int m = matrix.size(), n = matrix[0].size();
+        pre.resize(m + 1, vector<int>(n + 1));
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
+            }
+        }
+    }
+    
+    int sumRegion(int row1, int col1, int row2, int col2) {
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
+    }
+};
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * NumMatrix* obj = new NumMatrix(matrix);
+ * int param_1 = obj->sumRegion(row1,col1,row2,col2);
+ */
+```
+
+### **C++**
+
+```cpp
+type NumMatrix struct {
+	pre [][]int
+}
+
+func Constructor(matrix [][]int) NumMatrix {
+	m, n := len(matrix), len(matrix[0])
+	pre := make([][]int, m+1)
+	for i := 0; i < m+1; i++ {
+		pre[i] = make([]int, n+1)
+	}
+	for i := 1; i < m+1; i++ {
+		for j := 1; j < n+1; j++ {
+			pre[i][j] = pre[i-1][j] + pre[i][j-1] + -pre[i-1][j-1] + matrix[i-1][j-1]
+		}
+	}
+	return NumMatrix{pre}
+}
+
+func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
+	return this.pre[row2+1][col2+1] - this.pre[row2+1][col1] - this.pre[row1][col2+1] + this.pre[row1][col1]
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * obj := Constructor(matrix);
+ * param_1 := obj.SumRegion(row1,col1,row2,col2);
+ */
+```
+
 ### **...**
 
 ```

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

@@ -46,6 +46,8 @@ numMatrix.sumRegion(1, 2, 2, 4); // return 12 (i.e sum of the blue rectangele).
 
 ## Solutions
 
+Dynamic programming - 2D preSum.
+
 <!-- tabs:start -->
 
 ### **Python3**
@@ -54,17 +56,14 @@ numMatrix.sumRegion(1, 2, 2, 4); // return 12 (i.e sum of the blue rectangele).
 class NumMatrix:
 
     def __init__(self, matrix: List[List[int]]):
-        m = len(matrix)
-        if m > 0:
-            n = len(matrix[0])
-            self.sums = [[0] * (n + 1) for _ in range(m + 1)]
-            for i in range(m):
-                for j in range(n):
-                    self.sums[i + 1][j + 1] = self.sums[i][j + 1] + \
-                        self.sums[i + 1][j] - self.sums[i][j] + matrix[i][j]
+        m, n = len(matrix), len(matrix[0])
+        self.pre = [[0] * (n + 1) for _ in range(m + 1)]
+        for i in range(1, m + 1):
+            for j in range(1, n + 1):
+                self.pre[i][j] = self.pre[i - 1][j] + self.pre[i][j - 1] - self.pre[i - 1][j - 1] + matrix[i - 1][j - 1]
 
     def sumRegion(self, row1: int, col1: int, row2: int, col2: int) -> int:
-        return self.sums[row2 + 1][col2 + 1] - self.sums[row2 + 1][col1] - self.sums[row1][col2 + 1] + self.sums[row1][col1]
+        return self.pre[row2 + 1][col2 + 1] - self.pre[row2 + 1][col1] - self.pre[row1][col2 + 1] + self.pre[row1][col1]
 
 
 # Your NumMatrix object will be instantiated and called as such:
@@ -76,23 +75,20 @@ class NumMatrix:
 
 ```java
 class NumMatrix {
-    private int[][] sums;
+    private int[][] pre;
 
     public NumMatrix(int[][] matrix) {
-        int m = matrix.length;
-        if (m > 0) {
-            int n = matrix[0].length;
-            sums = new int[m + 1][n + 1];
-            for (int i = 0; i < m; ++i) {
-                for (int j = 0; j < n; ++j) {
-                    sums[i + 1][j + 1] = sums[i][j + 1] + sums[i + 1][j] - sums[i][j] + matrix[i][j];
-                }
+        int m = matrix.length, n = matrix[0].length;
+        pre = new int[m + 1][n + 1];
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
             }
         }
     }
-
+    
     public int sumRegion(int row1, int col1, int row2, int col2) {
-        return sums[row2 + 1][col2 + 1] - sums[row2 + 1][col1] - sums[row1][col2 + 1] + sums[row1][col1];
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
     }
 }
 
@@ -103,6 +99,67 @@ class NumMatrix {
  */
 ```
 
+### **C++**
+
+```cpp
+class NumMatrix {
+public:
+    vector<vector<int>> pre;
+
+    NumMatrix(vector<vector<int>>& matrix) {
+        int m = matrix.size(), n = matrix[0].size();
+        pre.resize(m + 1, vector<int>(n + 1));
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
+            }
+        }
+    }
+    
+    int sumRegion(int row1, int col1, int row2, int col2) {
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
+    }
+};
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * NumMatrix* obj = new NumMatrix(matrix);
+ * int param_1 = obj->sumRegion(row1,col1,row2,col2);
+ */
+```
+
+### **C++**
+
+```cpp
+type NumMatrix struct {
+	pre [][]int
+}
+
+func Constructor(matrix [][]int) NumMatrix {
+	m, n := len(matrix), len(matrix[0])
+	pre := make([][]int, m+1)
+	for i := 0; i < m+1; i++ {
+		pre[i] = make([]int, n+1)
+	}
+	for i := 1; i < m+1; i++ {
+		for j := 1; j < n+1; j++ {
+			pre[i][j] = pre[i-1][j] + pre[i][j-1] + -pre[i-1][j-1] + matrix[i-1][j-1]
+		}
+	}
+	return NumMatrix{pre}
+}
+
+func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
+	return this.pre[row2+1][col2+1] - this.pre[row2+1][col1] - this.pre[row1][col2+1] + this.pre[row1][col1]
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * obj := Constructor(matrix);
+ * param_1 := obj.SumRegion(row1,col1,row2,col2);
+ */
+```
+
 ### **...**
 
 ```

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

@@ -0,0 +1,24 @@
+class NumMatrix {
+public:
+    vector<vector<int>> pre;
+
+    NumMatrix(vector<vector<int>>& matrix) {
+        int m = matrix.size(), n = matrix[0].size();
+        pre.resize(m + 1, vector<int>(n + 1));
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
+            }
+        }
+    }
+    
+    int sumRegion(int row1, int col1, int row2, int col2) {
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
+    }
+};
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * NumMatrix* obj = new NumMatrix(matrix);
+ * int param_1 = obj->sumRegion(row1,col1,row2,col2);
+ */

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

@@ -0,0 +1,27 @@
+type NumMatrix struct {
+	pre [][]int
+}
+
+func Constructor(matrix [][]int) NumMatrix {
+	m, n := len(matrix), len(matrix[0])
+	pre := make([][]int, m+1)
+	for i := 0; i < m+1; i++ {
+		pre[i] = make([]int, n+1)
+	}
+	for i := 1; i < m+1; i++ {
+		for j := 1; j < n+1; j++ {
+			pre[i][j] = pre[i-1][j] + pre[i][j-1] + -pre[i-1][j-1] + matrix[i-1][j-1]
+		}
+	}
+	return NumMatrix{pre}
+}
+
+func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
+	return this.pre[row2+1][col2+1] - this.pre[row2+1][col1] - this.pre[row1][col2+1] + this.pre[row1][col1]
+}
+
+/**
+ * Your NumMatrix object will be instantiated and called as such:
+ * obj := Constructor(matrix);
+ * param_1 := obj.SumRegion(row1,col1,row2,col2);
+ */

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

@@ -1,21 +1,18 @@
 class NumMatrix {
-    private int[][] sums;
+    private int[][] pre;
 
     public NumMatrix(int[][] matrix) {
-        int m = matrix.length;
-        if (m > 0) {
-            int n = matrix[0].length;
-            sums = new int[m + 1][n + 1];
-            for (int i = 0; i < m; ++i) {
-                for (int j = 0; j < n; ++j) {
-                    sums[i + 1][j + 1] = sums[i][j + 1] + sums[i + 1][j] - sums[i][j] + matrix[i][j];
-                }
+        int m = matrix.length, n = matrix[0].length;
+        pre = new int[m + 1][n + 1];
+        for (int i = 1; i <= m; ++i) {
+            for (int j = 1; j <= n; ++j) {
+                pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
             }
         }
     }
 
     public int sumRegion(int row1, int col1, int row2, int col2) {
-        return sums[row2 + 1][col2 + 1] - sums[row2 + 1][col1] - sums[row1][col2 + 1] + sums[row1][col1];
+        return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
     }
 }
 

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

@@ -1,17 +1,14 @@
 class NumMatrix:
 
     def __init__(self, matrix: List[List[int]]):
-        m = len(matrix)
-        if m > 0:
-            n = len(matrix[0])
-            self.sums = [[0] * (n + 1) for _ in range(m + 1)]
-            for i in range(m):
-                for j in range(n):
-                    self.sums[i + 1][j + 1] = self.sums[i][j + 1] + \
-                        self.sums[i + 1][j] - self.sums[i][j] + matrix[i][j]
+        m, n = len(matrix), len(matrix[0])
+        self.pre = [[0] * (n + 1) for _ in range(m + 1)]
+        for i in range(1, m + 1):
+            for j in range(1, n + 1):
+                self.pre[i][j] = self.pre[i - 1][j] + self.pre[i][j - 1] - self.pre[i - 1][j - 1] + matrix[i - 1][j - 1]
 
     def sumRegion(self, row1: int, col1: int, row2: int, col2: int) -> int:
-        return self.sums[row2 + 1][col2 + 1] - self.sums[row2 + 1][col1] - self.sums[row1][col2 + 1] + self.sums[row1][col1]
+        return self.pre[row2 + 1][col2 + 1] - self.pre[row2 + 1][col1] - self.pre[row1][col2 + 1] + self.pre[row1][col1]
 
 
 # Your NumMatrix object will be instantiated and called as such: