题解 | #打印极值点下标#

#include <stdio.h>
int main(){
    //输入
    int num;
    while (scanf("%d", &num) != EOF){
        int arr[num];
        for (int i = 0; i < num; ++i) {
            scanf("%d", &arr[i]);
        }
        //判断并输出,第一个和最后一个数单独判断
        if (arr[0] != arr[1]){
            printf("0 ");
        }
        for (int i = 1; i < num - 1; ++i) {
            if (arr[i] > arr[i-1] && arr[i] > arr[i+1]){
                printf("%d ", i);
            }
            else if (arr[i] < arr[i-1] && arr[i] < arr[i+1]){
                printf("%d ", i);
            }
        }
        if (arr[num-1] != arr[num-2]){
            printf("%d", num-1);
        }
        printf("\n");
    }
    return 0;
}