规范格式

leetcode/0307.Range-Sum-Query---Mutable/307. Range Sum Query - Mutable.go

@@ -0,0 +1,68 @@
+package leetcode
+
+import (
+	"github.com/halfrost/LeetCode-Go/template"
+)
+
+// NumArray define
+type NumArray struct {
+	st *template.SegmentTree
+}
+
+// Constructor307 define
+func Constructor307(nums []int) NumArray {
+	st := template.SegmentTree{}
+	st.Init(nums, func(i, j int) int {
+		return i + j
+	})
+	return NumArray{st: &st}
+}
+
+// Update define
+func (this *NumArray) Update(i int, val int) {
+	this.st.Update(i, val)
+}
+
+//解法二 prefixSum，sumRange 时间复杂度 O(1)
+
+// // NumArray define
+// type NumArray307 struct {
+// 	prefixSum []int
+// 	data   []int
+// }
+
+// // Constructor307 define
+// func Constructor307(nums []int) NumArray307 {
+// 	data := make([]int, len(nums))
+// 	for i := 0; i < len(nums); i++ {
+// 		data[i] = nums[i]
+// 	}
+// 	for i := 1; i < len(nums); i++ {
+// 		nums[i] += nums[i-1]
+// 	}
+// 	return NumArray307{prefixSum: nums, data: data}
+// }
+
+// // Update define
+// func (this *NumArray307) Update(i int, val int) {
+// 	this.data[i] = val
+// 	this.prefixSum[0] = this.data[0]
+// 	for i := 1; i < len(this.data); i++ {
+// 		this.prefixSum[i] = this.prefixSum[i-1] + this.data[i]
+// 	}
+// }
+
+// // SumRange define
+// func (this *NumArray307) SumRange(i int, j int) int {
+// 	if i > 0 {
+// 		return this.prefixSum[j] - this.prefixSum[i-1]
+// 	}
+// 	return this.prefixSum[j]
+// }
+
+/**
+ * Your NumArray object will be instantiated and called as such:
+ * obj := Constructor(nums);
+ * obj.Update(i,val);
+ * param_2 := obj.SumRange(i,j);
+ */