c语言编写两个程序分别用来求逆序数和判定序数

1. 求逆序数的程序：

#include <stdio.h>

int merge(int arr[], int temp[], int left, int mid, int right) {
    int i, j, k;
    int count = 0;
    i = left;
    j = mid;
    k = left;

    while ((i <= mid - 1) && (j <= right)) {
        if (arr[i] <= arr[j]) {
            temp[k++] = arr[i++];
        } else {
            temp[k++] = arr[j++];
            count += (mid - i);
        }
    }

    while (i <= mid - 1) {
        temp[k++] = arr[i++];
    }

    while (j <= right) {
        temp[k++] = arr[j++];
    }

    for (i = left; i <= right; i++) {
        arr[i] = temp[i];
    }

    return count;
}

int mergeSort(int arr[], int temp[], int left, int right) {
    int mid, count = 0;
    if (right > left) {
        mid = (right + left) / 2;
        count = mergeSort(arr, temp, left, mid);
        count += mergeSort(arr, temp, mid + 1, right);
        count += merge(arr, temp, left, mid + 1, right);
    }

    return count;
}

int getInvCount(int arr[], int n) {
    int temp[n];
    return mergeSort(arr, temp, 0, n - 1);
}

int main() {
    int arr[] = {1, 20, 6, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    printf("逆序数为 %d", getInvCount(arr, n));
    return 0;
}

2. 判断序列是否有序的程序：

#include <stdio.h>

int isSorted(int arr[], int n) {
    int i;
    for (i = 1; i < n; i++) {
        if (arr[i] < arr[i - 1]) {
            return 0;
        }
    }
    return 1;
}

int main() {
    int arr[] = {1, 2, 3, 4, 5};
    int n = sizeof(arr) / sizeof(arr[0]);
    if (isSorted(arr, n)) {
        printf("该序列有序\n");
    } else {
        printf("该序列无序\n");
    }
    return 0;
}