1、线性搜索：
#include "date.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
// 希尔排序
void shellSort(int arr[], int n) {
for (int gap = n / 2; gap > 0; gap /= 2) {
for (int i = gap; i < n; i++) {
int temp = arr[i];
int j;
for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) {
arr[j] = arr[j - gap];
}
arr[j] = temp;
}
}
}
// 线性搜索并计算相同元素个数，打印序号
void linearSearchAndCount(int arr[], int n, int target) {
int count = 0;
printf("Found at indices: ");
for (int i = 0; i < n; i++) {
if (arr[i] == target) {
printf("%d ", i);
count++;
}
}
if (count == 0) {
printf("Not found.\n");
} else {
printf("\nTotal occurrences: %d\n", count);
}
}
// 打印数组
void printArray(int arr[], int n) {
for (int i = 0; i < n; i++) {
printf("%d ", arr[i]);
}
printf("\n");
}
int main() {
int times = getTime();
int n, target;
printf("Enter the size of the array: ");
scanf("%d", &n);
int *arr = (int *)malloc(n * sizeof(int));
if (arr == NULL) {
printf("Memory allocation failed.\n");
return 1;
}
srand(time(NULL));
for (int i = 0; i < n; i++) {
arr[i] = rand() % 100; // 假设生成0到99之间的随机数
}
printf("Original array: ");
printArray(arr, n); // 打印排序前的数组
shellSort(arr, n);
printf("Sorted array: ");
printArray(arr, n); // 打印排序后的数组
printf("Enter the target number to search: ");
scanf("%d", &target);
linearSearchAndCount(arr, n, target); // 线性搜索并打印结果
free(arr);
return 0;
}运行结果如下：
2、二分搜索：
#include "date.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
// 希尔排序
void shellSort(int arr[], int n) {
for (int gap = n / 2; gap > 0; gap /= 2) {
for (int i = gap; i < n; i++) {
int temp = arr[i];
int j;
for (j = i; j >= gap && arr[j - gap] > temp; j -= gap)
arr[j] = arr[j - gap];
arr[j] = temp;
}
}
}
// 线性搜索计算相同元素
int countAndPrintSame(int arr[], int n, int target) {
int count = 0;
int firstIndex = -1;
for (int i = 0; i < n; i++) {
if (arr[i] == target) {
if (firstIndex == -1) firstIndex = i;
count++;
}
}
if (count > 0) {
printf("Found %d occurrences of %d, first at index %d.\n", count, target, firstIndex);
} else {
printf("Element %d not found in the array.\n", target);
}
return count;
}
// 二分查找
int binarySearch(int arr[], int l, int r, int x) {
while (l <= r) {
int m = l + (r - l) / 2;
// 检查mid是否是要找的元素
if (arr[m] == x) return m;
// 如果元素小于mid，则它只可能出现在左子数组中
if (arr[m] < x)
l = m + 1;
// 否则，元素只能出现在右子数组中
else
r = m - 1;
}
// 如果到达这里，元素不在数组中
return -1;
}
int main() {
int times = getTime();
int n, target;
printf("Enter the number of elements: ");
scanf("%d", &n);
int* arr = (int*)malloc(n * sizeof(int));
srand(time(NULL));
printf("Generated array:\n ");
for (int i = 0; i < n; i++) {
arr[i] = rand() % 100; // 生成0到99之间的随机数
printf("%d ", arr[i]);
}
printf("\n");
shellSort(arr, n);
printf("Sorted array: \n");
for (int i = 0; i < n; i++) {
printf("%d ", arr[i]);
}
printf("\n");
printf("Enter the element to search: ");
scanf("%d", &target);
int result = binarySearch(arr, 0, n - 1, target);
if (result != -1) {
printf("Element found at index %d.\n", result);
countAndPrintSame(arr, n, target);
} else {
printf("Element not found.\n");
}
free(arr);
return 0;
}运行结果如下：
3、 插值搜索：
#include "date.h"
#include <stdio.h>
#include <stdlib.h>
#include <time.h>
// 希尔排序对整数数组arr进行排序。
// 通过缩小增量序列（gap）逐渐逼近最终的排序状态。
void shellSort(int arr[], int n) {
for (int gap = n / 2; gap > 0; gap /= 2) {
for (int i = gap; i < n; i++) {
int temp = arr[i];
int j;
for (j = i; j >= gap && arr[j - gap] > temp; j -= gap) {
arr[j] = arr[j - gap];
}
arr[j] = temp;
}
}
}
// 插值搜索是一种在有序数组中查找特定元素的算法，基于元素值分布的特性来预测目标值可能的位置，从而减少搜索空间。
int interpolationSearch(int arr[], int n, int x) {
int low = 0, high = n - 1;
while (low <= high && x >= arr[low] && x <= arr[high]) {
if (high == low) {
if (arr[low] == x) return low;
return -1;
}
int pos = low + (((double)(high - low) / (arr[high] - arr[low])) * (x - arr[low]));
if (arr[pos] == x) return pos;
if (arr[pos] < x)
low = pos + 1;
else
high = pos - 1;
}
return -1;
}
int main() {
int times = getTime();
int n, i, searchValue;
printf("Enter the number of elements: ");
scanf("%d", &n);
// 动态分配内存
int *arr = (int*)malloc(n * sizeof(int));
if (!arr) {
printf("Memory allocation failed\n");
return 1;
}
// 生成随机数并填充数组
srand(time(NULL));
for (i = 0; i < n; i++) {
arr[i] = rand() % 100;
}
// 打印原始数组
printf("Original array: ");
for (i = 0; i < n; i++) {
printf("%d ", arr[i]);
}
printf("\n");
// 对数组进行希尔排序
shellSort(arr, n);
// 打印排序后的数组
printf("Sorted array: \n");
for (i = 0; i < n; i++) {
printf("%d ", arr[i]);
}
printf("\n");
// 读取要搜索的值并进行插值搜索
printf("Enter the value to search: \n");
scanf("%d", &searchValue);
// 插值搜索
int index = interpolationSearch(arr, n, searchValue);
// 遍历数组以计算并打印目标值的所有出现的位置。
if (index != -1) {
printf("Element found at index %d\n", index);
} else {
printf("Element not found\n");
}
// 如果搜索一个值，只要找到就打印。
// 计算出现次数，需要遍历数组。
int count = 0;
for (i = 0; i < n; i++) {
if (arr[i] == searchValue) {
count++;
printf("Found %d at index %d\n", searchValue, i);
}
}
printf("Total occurrences of %d: %d\n", searchValue, count);
free(arr);
return 0;
}运行结果如下：
