50 lines
1.2 KiB
Go
50 lines
1.2 KiB
Go
// File: binary_search_insertion.go
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// Created Time: 2023-08-23
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// Author: Reanon (793584285@qq.com)
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package chapter_searching
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/* Binary search for insertion point (no duplicate elements) */
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func binarySearchInsertionSimple(nums []int, target int) int {
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// Initialize double closed interval [0, n-1]
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i, j := 0, len(nums)-1
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for i <= j {
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// Calculate midpoint index m
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m := i + (j-i)/2
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if nums[m] < target {
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// Target is in interval [m+1, j]
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i = m + 1
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} else if nums[m] > target {
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// Target is in interval [i, m-1]
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j = m - 1
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} else {
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// Found target, return insertion point m
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return m
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}
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}
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// Did not find target, return insertion point i
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return i
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}
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/* Binary search for insertion point (with duplicate elements) */
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func binarySearchInsertion(nums []int, target int) int {
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// Initialize double closed interval [0, n-1]
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i, j := 0, len(nums)-1
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for i <= j {
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// Calculate midpoint index m
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m := i + (j-i)/2
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if nums[m] < target {
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// Target is in interval [m+1, j]
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i = m + 1
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} else if nums[m] > target {
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// Target is in interval [i, m-1]
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j = m - 1
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} else {
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// First element less than target is in interval [i, m-1]
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j = m - 1
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}
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}
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// Return insertion point i
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return i
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}
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