1104. Sum of Number Segments

注意double类型输入为%ld~其他没什么

#include <stdio.h>/*4，6,6,4 第i个元素，左边i种组合，右边n-i+1种）*/int main(){int n;double ans=0,num;scanf("%d", &n);for (int i = 1; i <= n;i++) {scanf("%lf",&num);ans += num*i*(n - i + 1);}printf("%.2f", ans);return 0;}