C语言的10大基础算法_c语言的常见算法

1. 排序算法：冒泡排序、选择排序、插入排序、快速排序、归并排序等

2. 查找算法：二分查找

3. 字符串匹配算法：暴力匹配、KMP算法、Boyer-Moore算法等

4. 数学算法：质数判定、最大公约数、最小公倍数等

5. 统计算法：排序统计法、哈希统计法等

6. 图论算法：深度优先搜索、广度优先搜索、最短路径算法等

7. 动态规划算法：最长递增子序列、最大子段和等

8. 贪心算法：霍夫曼编码、活动选择等

9. 分治算法：归并排序、快速排序、FFT算法等

10. 模拟算法：进程调度模拟、图形旋转等

11. 冒泡排序

#include <stdio.h>

void bubble_sort(int arr[], int len) {
    int i, j, temp;
    for (i = 0; i < len - 1; i++) {
        for (j = 0; j < len - 1 - i; j++) {
            if (arr[j] > arr[j + 1]) {
                temp = arr[j];
                arr[j] = arr[j + 1];
                arr[j + 1] = temp;
            }
        }
    }
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    bubble_sort(arr, len);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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2. 快速排序

#include <stdio.h>

void quick_sort(int arr[], int left, int right) {
    if (left >= right) return;
    int i = left, j = right, pivot = arr[left];
    while (i < j) {
        while (i < j && arr[j] >= pivot) j--;
        arr[i] = arr[j];
        while (i < j && arr[i] <= pivot) i++;
        arr[j] = arr[i];
    }
    arr[i] = pivot;
    quick_sort(arr, left, i - 1);
    quick_sort(arr, i + 1, right);
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    quick_sort(arr, 0, len - 1);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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3. 选择排序

#include <stdio.h>

void select_sort(int arr[], int len) {
    int i, j, min_index, temp;
    for (i = 0; i < len - 1; i++) {
        min_index = i;
        for (j = i + 1; j < len; j++) {
            if (arr[j] < arr[min_index]) {
                min_index = j;
            }
        }
        if (min_index != i) {
            temp = arr[i];
            arr[i] = arr[min_index];
            arr[min_index] = temp;
        }
    }
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    select_sort(arr, len);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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4. 插入排序

#include <stdio.h>

void insert_sort(int arr[], int len) {
    int i, j, temp;
    for (i = 1; i < len; i++) {
        temp = arr[i];
        j = i - 1;
        while (j >= 0 && arr[j] > temp) {
            arr[j + 1] = arr[j];
            j--;
        }
        arr[j + 1] = temp;
    }
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    insert_sort(arr, len);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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5. 归并排序

#include <stdio.h>
#include <stdlib.h>

void merge(int arr[], int left, int mid, int right, int temp[]) {
    int i = left, j = mid + 1, k = 0;
    while (i <= mid && j <= right) {
        if (arr[i] <= arr[j]) {
            temp[k++] = arr[i++];
        } else {
            temp[k++] = arr[j++];
        }
    }
    while (i <= mid) {
        temp[k++] = arr[i++];
    }
    while (j <= right) {
        temp[k++] = arr[j++];
    }
    for (i = 0; i < k; i++) {
        arr[left + i] = temp[i];
    }
}

void merge_sort(int arr[], int left, int right, int temp[]) {
    if (left >= right) return;
    int mid = (left + right) / 2;
    merge_sort(arr, left, mid, temp);
    merge_sort(arr, mid + 1, right, temp);
    merge(arr, left, mid, right, temp);
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    int *temp = (int *) malloc(len * sizeof(int));
    merge_sort(arr, 0, len - 1, temp);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    free(temp);
    return 0;
}
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6. 希尔排序

#include <stdio.h>

void shell_sort(int arr[], int len) {
    int gap, i, j, temp;
    for (gap = len / 2; gap > 0; gap /= 2) {
        for (i = gap; i < len; i++) {
            temp = arr[i];
            for (j = i - gap; j >= 0 && arr[j] > temp; j -= gap) {
                arr[j + gap] = arr[j];
            }
            arr[j + gap] = temp;
        }
    }
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    shell_sort(arr, len);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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7. 堆排序

#include <stdio.h>

void adjust_heap(int arr[], int i, int len) {
    int left = 2 * i + 1, right = 2 * i + 2, max_index = i, temp;
    if (left < len && arr[left] > arr[max_index]) {
        max_index = left;
    }
    if (right < len && arr[right] > arr[max_index]) {
        max_index = right;
    }
    if (max_index != i) {
        temp = arr[i];
        arr[i] = arr[max_index];
        arr[max_index] = temp;
        adjust_heap(arr, max_index, len);
    }
}

void build_heap(int arr[], int len) {
    int i;
    for (i = len / 2 - 1; i >= 0; i--) {
        adjust_heap(arr, i, len);
    }
}

void heap_sort(int arr[], int len) {
    int i, temp;
    build_heap(arr, len);
    for (i = len - 1; i > 0; i--) {
        temp = arr[0];
        arr[0] = arr[i];
        arr[i] = temp;
        adjust_heap(arr, 0, i);
    }
}

int main() {
    int arr[] = {6, 5, 3, 1, 8, 7, 2, 4};
    int len = sizeof(arr) / sizeof(arr[0]);
    heap_sort(arr, len);
    for (int i = 0; i < len; i++) {
        printf("%d ", arr[i]);
    }
    printf("\n");
    return 0;
}
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8. 计数排序

#include <stdio.h>
#include <stdlib.h>

void count_sort(int arr[], int len) {
    int i, j, max = arr[0], *count, *bucket;
    for (i = 1; i < len; i++) {
        if (arr[i] > max) {
            max = arr[i];
        }
    }
    count = (int *) malloc(sizeof(int) * (max + 1));
    bucket = (int *) malloc(sizeof(int) * len);
    for (i = 0; i <= max; i++) {
        count[i] = 0;
    }
    for (i = 0; i < len; i++) {
        count[arr[i]]++;
    }
    for (i = 1; i <= max; i++) {
        count[i] += count[i - 1];
    }
    for (i = len - 1; i >= 0; i--) {
        j = count[arr[i]] - 1;
        bucket[j] = arr[i];
        count[arr[i]]--;
    }

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