用三分法求给定数组的最大值、最小值、数组的和的C++代码

以下是用三分法求给定数组的最大值、最小值、数组的和的C代码：

#include <stdio.h>

int main() {
    int n;
    scanf("%d", &n);
    int a[n];
    for (int i = ; i < n; i++) {
        scanf("%d", &a[i]);
    }

    int l = , r = n - 1;
    int max_val = a[], min_val = a[], sum = ;

    while (l <= r) {
        int mid = (l + r) / 2;
        if (a[mid] > max_val) {
            max_val = a[mid];
        }
        if (a[mid] < min_val) {
            min_val = a[mid];
        }
        sum += a[mid];
        if (mid == l && mid == r) {
            break;
        }
        if (mid == l) {
            l = mid + 1;
        } else if (mid == r) {
            r = mid - 1;
        } else if (a[mid - 1] > a[mid + 1]) {
            r = mid - 1;
        } else {
            l = mid + 1;
        }
    }

    printf("最大值：%d\n", max_val);
    printf("最小值：%d\n", min_val);
    printf("数组的和：%d\n", sum);

    return ;
}