59 lines
1.4 KiB
C++
59 lines
1.4 KiB
C++
#include "stdio.h"
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/*
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二分插入排序：通过二分查找找到插入位置，然后将元素插入到指定位置。
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*/
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// 统计待排序数据的比较次数
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int compare_count = 0;
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// 递归二分查找插入位置
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int binary_search(int v[], int left, int right, int n)
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{
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if (left > right)
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return left; // 递归边界，此处不统计比较次数
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int mid = (left + right) >> 1;
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compare_count++; // 统计比较次数
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if (v[mid] > v[n])
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return binary_search(v, left, mid - 1, n);
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else
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return binary_search(v, mid + 1, right, n);
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}
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// 将新的元素插入到指定位置，并将后续元素后移
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void insert(int *v, int k, int n)
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{
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int i;
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int tmp = v[n];
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for (i = n - 1; i >= k; i--)
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{
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v[i + 1] = v[i];
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}
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v[k] = tmp;
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}
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void binary_insertion_sort(int v[], int n)
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{
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int i;
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for (i = 1; i < n; i++)
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{ // 从第二个元素开始，依次插入到前面已经排好序的序列中
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int place = binary_search(v, 0, i - 1, i);
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insert(v, place, i);
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}
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}
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int main()
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{
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FILE *infile, *outfile;
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int buffer[1001];
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infile = fopen("a.in", "rb");
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fread(buffer, 4, 1001, infile);
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fclose(infile);
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int N = buffer[0];
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binary_insertion_sort(&(buffer[1]), N);
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buffer[0] = compare_count;
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outfile = fopen("a.out", "wb");
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fwrite(buffer, 4, N + 1, outfile);
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fclose(outfile);
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return 0;
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}
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