mirror of
https://github.com/halfrost/LeetCode-Go.git
synced 2025-07-07 01:44:56 +08:00
69 lines
1.4 KiB
Go
69 lines
1.4 KiB
Go
package leetcode
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import (
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"github.com/halfrost/LeetCode-Go/template"
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)
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// NumArray define
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type NumArray struct {
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st *template.SegmentTree
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}
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// Constructor307 define
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func Constructor307(nums []int) NumArray {
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st := template.SegmentTree{}
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st.Init(nums, func(i, j int) int {
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return i + j
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})
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return NumArray{st: &st}
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}
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// Update define
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func (this *NumArray) Update(i int, val int) {
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this.st.Update(i, val)
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}
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//解法二 prefixSum，sumRange 时间复杂度 O(1)
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// // NumArray define
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// type NumArray307 struct {
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// prefixSum []int
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// data []int
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// }
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// // Constructor307 define
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// func Constructor307(nums []int) NumArray307 {
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// data := make([]int, len(nums))
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// for i := 0; i < len(nums); i++ {
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// data[i] = nums[i]
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// }
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// for i := 1; i < len(nums); i++ {
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// nums[i] += nums[i-1]
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// }
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// return NumArray307{prefixSum: nums, data: data}
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// }
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// // Update define
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// func (this *NumArray307) Update(i int, val int) {
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// this.data[i] = val
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// this.prefixSum[0] = this.data[0]
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// for i := 1; i < len(this.data); i++ {
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// this.prefixSum[i] = this.prefixSum[i-1] + this.data[i]
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// }
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// }
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// // SumRange define
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// func (this *NumArray307) SumRange(i int, j int) int {
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// if i > 0 {
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// return this.prefixSum[j] - this.prefixSum[i-1]
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// }
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// return this.prefixSum[j]
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// }
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/**
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* Your NumArray object will be instantiated and called as such:
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* obj := Constructor(nums);
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* obj.Update(i,val);
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* param_2 := obj.SumRange(i,j);
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*/
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