#include<stdio.h> #include<stdlib.h> int main() { int n,a[1000]; scanf_s("%d", &n); for (int m = 0; m < n; m++) { scanf_s("%d", &a[m]); } mergesort(a, 0, n); for (int m = 0; m < n; m++) { printf("%d", a[m]); } return 0; } void merge(int *a, int low, int mid, int high) { int i, j, k = low; int b[1000] = { 0 }; i = low; j = mid + 1; while (i <= mid && j <= high) { if (a[i] <= a[j]) { b[k] = a[i++]; } else b[k] = a[j++]; k++; } while (i <= mid) b[k++] = a[i++]; while (j <= high) b[k++] = a[j++]; for (k = low; k <= high; k++) { a[k] = b[k]; } } void mergesort(int *a, int low, int high) { int mid = (low + high) / 2; if (low < high) { mergesort(a, low, mid); mergesort(a, mid + 1, high); merge(a, low, mid, high); } }修改错误

在程序中发现一个错误，`mergesort(a, 0, n)`应该改为`mergesort(a, 0, n-1)`，因为数组下标是从0开始的。修改后的代码如下：

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

void merge(int *a, int low, int mid, int high) {
    int i, j, k = low;
    int b[1000] = { 0 };
    i = low;
    j = mid + 1;
    while (i <= mid && j <= high) {
        if (a[i] <= a[j]) {
             b[k] = a[i++];
        } else {
            b[k] = a[j++];
        }
        k++;
    }
    while (i <= mid) {
        b[k++] = a[i++];
    }
    while (j <= high) {
        b[k++] = a[j++];
    }
    for (k = low; k <= high; k++) {
        a[k] = b[k];
    }
}

void mergesort(int *a, int low, int high) {
    int mid = (low + high) / 2;
    if (low < high) {
        mergesort(a, low, mid);
        mergesort(a, mid + 1, high);
        merge(a, low, mid, high);
    }
}

int main() {
    int n,a[1000];
    scanf_s("%d", &n);
    for (int m = 0; m < n; m++) {
        scanf_s("%d", &a[m]);
    }
    mergesort(a, 0, n-1);
    for (int m = 0; m < n; m++) {
        printf("%d ", a[m]);
    }
    return 0;
}