mirror of
https://github.com/krahets/hello-algo.git
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e720aa2d24
* Sync recent changes to the revised Word. * Revised the preface chapter * Revised the introduction chapter * Revised the computation complexity chapter * Revised the chapter data structure * Revised the chapter array and linked list * Revised the chapter stack and queue * Revised the chapter hashing * Revised the chapter tree * Revised the chapter heap * Revised the chapter graph * Revised the chapter searching * Reivised the sorting chapter * Revised the divide and conquer chapter * Revised the chapter backtacking * Revised the DP chapter * Revised the greedy chapter * Revised the appendix chapter * Revised the preface chapter doubly * Revised the figures
114 lines
3 KiB
C
114 lines
3 KiB
C
/**
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* File: array.c
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* Created Time: 2022-12-20
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* Author: MolDuM (moldum@163.com)
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*/
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#include "../utils/common.h"
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/* 随机访问元素 */
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int randomAccess(int *nums, int size) {
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// 在区间 [0, size) 中随机抽取一个数字
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int randomIndex = rand() % size;
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// 获取并返回随机元素
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int randomNum = nums[randomIndex];
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return randomNum;
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}
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/* 扩展数组长度 */
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int *extend(int *nums, int size, int enlarge) {
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// 初始化一个扩展长度后的数组
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int *res = (int *)malloc(sizeof(int) * (size + enlarge));
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// 将原数组中的所有元素复制到新数组
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for (int i = 0; i < size; i++) {
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res[i] = nums[i];
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}
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// 初始化扩展后的空间
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for (int i = size; i < size + enlarge; i++) {
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res[i] = 0;
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}
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// 返回扩展后的新数组
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return res;
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}
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/* 在数组的索引 index 处插入元素 num */
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void insert(int *nums, int size, int num, int index) {
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// 把索引 index 以及之后的所有元素向后移动一位
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for (int i = size - 1; i > index; i--) {
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nums[i] = nums[i - 1];
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}
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// 将 num 赋给 index 处的元素
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nums[index] = num;
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}
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/* 删除索引 index 处的元素 */
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// 注意：stdio.h 占用了 remove 关键词
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void removeItem(int *nums, int size, int index) {
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// 把索引 index 之后的所有元素向前移动一位
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for (int i = index; i < size - 1; i++) {
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nums[i] = nums[i + 1];
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}
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}
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/* 遍历数组 */
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void traverse(int *nums, int size) {
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int count = 0;
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// 通过索引遍历数组
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for (int i = 0; i < size; i++) {
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count += nums[i];
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}
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}
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/* 在数组中查找指定元素 */
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int find(int *nums, int size, int target) {
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for (int i = 0; i < size; i++) {
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if (nums[i] == target)
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return i;
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}
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return -1;
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}
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/* Driver Code */
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int main() {
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/* 初始化数组 */
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int size = 5;
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int arr[5];
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printf("数组 arr = ");
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printArray(arr, size);
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int nums[] = {1, 3, 2, 5, 4};
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printf("数组 nums = ");
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printArray(nums, size);
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/* 随机访问 */
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int randomNum = randomAccess(nums, size);
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printf("在 nums 中获取随机元素 %d", randomNum);
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/* 长度扩展 */
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int enlarge = 3;
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int *res = extend(nums, size, enlarge);
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size += enlarge;
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printf("将数组长度扩展至 8 ，得到 nums = ");
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printArray(res, size);
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/* 插入元素 */
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insert(res, size, 6, 3);
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printf("在索引 3 处插入数字 6 ，得到 nums = ");
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printArray(res, size);
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/* 删除元素 */
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removeItem(res, size, 2);
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printf("删除索引 2 处的元素，得到 nums = ");
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printArray(res, size);
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/* 遍历数组 */
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traverse(res, size);
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/* 查找元素 */
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int index = find(res, size, 3);
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printf("在 res 中查找元素 3 ，得到索引 = %d\n", index);
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/* 释放内存 */
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free(res);
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return 0;
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}
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