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Commit 1d34870

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feat: add solutions to lcof2 problem: No.013
1 parent fbf1f14 commit 1d34870

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5 files changed

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‎lcof2/剑指 Offer II 013. 二维子矩阵的和/README.md‎

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<p><img src="https://cdn.jsdelivr.net/gh/doocs/leetcode@main/lcof2/%E5%89%91%E6%8C%87%20Offer%20II%20013.%20%E4%BA%8C%E7%BB%B4%E5%AD%90%E7%9F%A9%E9%98%B5%E7%9A%84%E5%92%8C/images/1626332422-wUpUHT-image.png" style="width: 200px;" /></p>
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<pre>
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<strong>输入:</strong>
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<strong>输入:</strong>
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[&quot;NumMatrix&quot;,&quot;sumRegion&quot;,&quot;sumRegion&quot;,&quot;sumRegion&quot;]
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[[[[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]]
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<strong>输出:</strong>
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<strong>输出:</strong>
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[null, 8, 11, 12]
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<strong>解释:</strong>
@@ -60,22 +60,122 @@ numMatrix.sumRegion(1, 2, 2, 4); // return 12 (蓝色矩形框的元素总和)
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<!-- 这里可写通用的实现逻辑 -->
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动态规划-二维前缀和。
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<!-- tabs:start -->
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### **Python3**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```python
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class NumMatrix:
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def __init__(self, matrix: List[List[int]]):
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m, n = len(matrix), len(matrix[0])
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self.pre = [[0] * (n + 1) for _ in range(m + 1)]
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for i in range(1, m + 1):
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for j in range(1, n + 1):
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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]
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def sumRegion(self, row1: int, col1: int, row2: int, col2: int) -> int:
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return self.pre[row2 + 1][col2 + 1] - self.pre[row2 + 1][col1] - self.pre[row1][col2 + 1] + self.pre[row1][col1]
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# Your NumMatrix object will be instantiated and called as such:
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# obj = NumMatrix(matrix)
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# param_1 = obj.sumRegion(row1,col1,row2,col2)
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```
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### **Java**
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<!-- 这里可写当前语言的特殊实现逻辑 -->
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```java
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class NumMatrix {
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private int[][] pre;
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public NumMatrix(int[][] matrix) {
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int m = matrix.length, n = matrix[0].length;
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pre = new int[m + 1][n + 1];
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for (int i = 1; i <= m; ++i) {
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for (int j = 1; j <= n; ++j) {
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pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
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}
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}
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}
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public int sumRegion(int row1, int col1, int row2, int col2) {
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return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
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}
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}
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* NumMatrix obj = new NumMatrix(matrix);
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* int param_1 = obj.sumRegion(row1,col1,row2,col2);
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*/
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```
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### **C++**
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```cpp
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class NumMatrix {
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public:
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vector<vector<int>> pre;
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NumMatrix(vector<vector<int>>& matrix) {
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int m = matrix.size(), n = matrix[0].size();
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pre.resize(m + 1, vector<int>(n + 1));
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for (int i = 1; i <= m; ++i) {
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for (int j = 1; j <= n; ++j) {
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pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
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}
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}
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}
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int sumRegion(int row1, int col1, int row2, int col2) {
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return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
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}
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};
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* NumMatrix* obj = new NumMatrix(matrix);
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* int param_1 = obj->sumRegion(row1,col1,row2,col2);
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*/
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```
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### **Go**
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```go
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type NumMatrix struct {
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pre [][]int
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}
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func Constructor(matrix [][]int) NumMatrix {
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m, n := len(matrix), len(matrix[0])
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pre := make([][]int, m+1)
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for i := 0; i < m+1; i++ {
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pre[i] = make([]int, n+1)
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}
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for i := 1; i < m+1; i++ {
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for j := 1; j < n+1; j++ {
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pre[i][j] = pre[i-1][j] + pre[i][j-1] + -pre[i-1][j-1] + matrix[i-1][j-1]
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}
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}
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return NumMatrix{pre}
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}
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func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
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return this.pre[row2+1][col2+1] - this.pre[row2+1][col1] - this.pre[row1][col2+1] + this.pre[row1][col1]
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}
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* obj := Constructor(matrix);
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* param_1 := obj.SumRegion(row1,col1,row2,col2);
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*/
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```
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### **...**
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Original file line numberDiff line numberDiff line change
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class NumMatrix {
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public:
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vector<vector<int>> pre;
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NumMatrix(vector<vector<int>>& matrix) {
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int m = matrix.size(), n = matrix[0].size();
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pre.resize(m + 1, vector<int>(n + 1));
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for (int i = 1; i <= m; ++i) {
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for (int j = 1; j <= n; ++j) {
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pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
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}
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}
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}
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int sumRegion(int row1, int col1, int row2, int col2) {
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return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
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}
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};
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* NumMatrix* obj = new NumMatrix(matrix);
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* int param_1 = obj->sumRegion(row1,col1,row2,col2);
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*/
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Original file line numberDiff line numberDiff line change
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type NumMatrix struct {
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pre [][]int
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}
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func Constructor(matrix [][]int) NumMatrix {
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m, n := len(matrix), len(matrix[0])
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pre := make([][]int, m+1)
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for i := 0; i < m+1; i++ {
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pre[i] = make([]int, n+1)
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}
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for i := 1; i < m+1; i++ {
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for j := 1; j < n+1; j++ {
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pre[i][j] = pre[i-1][j] + pre[i][j-1] + -pre[i-1][j-1] + matrix[i-1][j-1]
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}
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}
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return NumMatrix{pre}
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}
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func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {
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return this.pre[row2+1][col2+1] - this.pre[row2+1][col1] - this.pre[row1][col2+1] + this.pre[row1][col1]
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}
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* obj := Constructor(matrix);
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* param_1 := obj.SumRegion(row1,col1,row2,col2);
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*/
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class NumMatrix {
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private int[][] pre;
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public NumMatrix(int[][] matrix) {
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int m = matrix.length, n = matrix[0].length;
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pre = new int[m + 1][n + 1];
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for (int i = 1; i <= m; ++i) {
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for (int j = 1; j <= n; ++j) {
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pre[i][j] = pre[i - 1][j] + pre[i][j - 1] - pre[i - 1][j - 1] + matrix[i - 1][j - 1];
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}
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}
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}
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public int sumRegion(int row1, int col1, int row2, int col2) {
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return pre[row2 + 1][col2 + 1] - pre[row2 + 1][col1] - pre[row1][col2 + 1] + pre[row1][col1];
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}
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}
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/**
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* Your NumMatrix object will be instantiated and called as such:
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* NumMatrix obj = new NumMatrix(matrix);
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* int param_1 = obj.sumRegion(row1,col1,row2,col2);
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*/
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class NumMatrix:
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def __init__(self, matrix: List[List[int]]):
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m, n = len(matrix), len(matrix[0])
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self.pre = [[0] * (n + 1) for _ in range(m + 1)]
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for i in range(1, m + 1):
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for j in range(1, n + 1):
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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]
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def sumRegion(self, row1: int, col1: int, row2: int, col2: int) -> int:
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return self.pre[row2 + 1][col2 + 1] - self.pre[row2 + 1][col1] - self.pre[row1][col2 + 1] + self.pre[row1][col1]
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# Your NumMatrix object will be instantiated and called as such:
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# obj = NumMatrix(matrix)
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# param_1 = obj.sumRegion(row1,col1,row2,col2)

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