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	`1`	`+`
	`2`	`+# 0304.range-sum-query-2d-immutable`
	`3`	`+`
	`4`	`+![链表](../../static/image/304.png)`
	`5`	`+`
	`6`	+```text
	`7`	`+304. 二维区域和检索 - 矩阵不可变`
	`8`	`+`
	`9`	`+给定一个二维矩阵,计算其子矩形范围内元素的总和,该子矩阵的左上角为 (row1, col1) ,右下角为 (row2, col2) 。`
	`10`	`+`
	`11`	`+`
	`12`	`+上图子矩阵左上角 (row1, col1) = (2, 1) ,右下角(row2, col2) = (4, 3),该子矩形内元素的总和为 8。`
	`13`	`+`
	`14`	`+`
	`15`	`+`
	`16`	`+示例:`
	`17`	`+`
	`18`	`+给定 matrix = [`
	`19`	`+ [3, 0, 1, 4, 2],`
	`20`	`+ [5, 6, 3, 2, 1],`
	`21`	`+ [1, 2, 0, 1, 5],`
	`22`	`+ [4, 1, 0, 1, 7],`
	`23`	`+ [1, 0, 3, 0, 5]`
	`24`	`+]`
	`25`	`+`
	`26`	`+sumRegion(2, 1, 4, 3) -> 8`
	`27`	`+sumRegion(1, 1, 2, 2) -> 11`
	`28`	`+sumRegion(1, 2, 2, 4) -> 12`
	`29`	`+`
	`30`	`+`
	`31`	`+提示:`
	`32`	`+`
	`33`	`+你可以假设矩阵不可变。`
	`34`	`+会多次调用 sumRegion 方法。`
	`35`	`+你可以假设 row1 ≤ row2 且 col1 ≤ col2 。`
	`36`	`+`
	`37`	`+来源:力扣(LeetCode)`
	`38`	`+链接:https://leetcode-cn.com/problems/range-sum-query-2d-immutable`
	`39`	`+著作权归领扣网络所有。商业转载请联系官方授权,非商业转载请注明出处。`
	`40`	+```

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	`1`	`+package immutable`
	`2`	`+`
	`3`	`+import "fmt"`
	`4`	`+`
	`5`	`+func Run() {`
	`6`	`+ matrix := [][]int{`
	`7`	`+ []int{3, 0, 1, 4, 2},`
	`8`	`+ []int{5, 6, 3, 2, 1},`
	`9`	`+ []int{1, 2, 0, 1, 5},`
	`10`	`+ []int{4, 1, 0, 1, 7},`
	`11`	`+ []int{1, 0, 3, 0, 5},`
	`12`	`+ }`
	`13`	`+ c := Constructor(matrix)`
	`14`	`+ sum := c.SumRegion(2, 1, 4, 3)`
	`15`	`+ fmt.Println(sum)`
	`16`	`+}`
	`17`	`+`
	`18`	`+type NumMatrix struct {`
	`19`	`+ sums [][]int`
	`20`	`+}`
	`21`	`+`
	`22`	`+func Constructor(matrix [][]int) NumMatrix {`
	`23`	`+ sums := make([][]int, len(matrix))`
	`24`	`+ for i, row := range matrix {`
	`25`	`+ sums[i] = make([]int, len(row)+1)`
	`26`	`+ for i2, v := range row {`
	`27`	`+ sums[i][i2+1] = sums[i][i2] + v`
	`28`	`+ }`
	`29`	`+ }`
	`30`	`+ return NumMatrix{sums: sums}`
	`31`	`+}`
	`32`	`+`
	`33`	`+func (this *NumMatrix) SumRegion(row1 int, col1 int, row2 int, col2 int) int {`
	`34`	`+ sum := 0`
	`35`	`+ for i := row1; i <= row2; i++ {`
	`36`	`+ sum += this.sums[i][col2+1] - this.sums[i][col1]`
	`37`	`+ }`
	`38`	`+ return sum`
	`39`	`+}`
	`40`	`+`
	`41`	`+/**`
	`42`	`+ * Your NumMatrix object will be instantiated and called as such:`
	`43`	`+ * obj := Constructor(matrix);`
	`44`	`+ * param_1 := obj.SumRegion(row1,col1,row2,col2);`
	`45`	`+ */`

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