PAT A1104 测试点3问题

题目

1104 Sum of Number Segments (20分) Given a sequence of positive numbers, a segment is defined to be a consecutive subsequence. For example, given the sequence { 0.1, 0.2, 0.3, 0.4 }, we have 10 segments: (0.1) (0.1, 0.2) (0.1, 0.2, 0.3) (0.1, 0.2, 0.3, 0.4) (0.2) (0.2, 0.3) (0.2, 0.3, 0.4) (0.3) (0.3, 0.4) and (0.4).

Now given a sequence, you are supposed to find the sum of all the numbers in all the segments. For the previous example, the sum of all the 10 segments is 0.1 + 0.3 + 0.6 + 1.0 + 0.2 + 0.5 + 0.9 + 0.3 + 0.7 + 0.4 = 5.0.

Input Specification: Each input file contains one test case. For each case, the first line gives a positive integer N, the size of the sequence which is no more than 10 ​5 ​​ . The next line contains N positive numbers in the sequence, each no more than 1.0, separated by a space.

Output Specification: For each test case, print in one line the sum of all the numbers in all the segments, accurate up to 2 decimal places.

Sample Input: 4 0.1 0.2 0.3 0.4 Sample Output: 5.00

测试点3修改了数据，导致使用double输入输出不能AC

使用long double输入输出即可注意long double输入输出需要使用%Lf%Lf的L必须大写 #include <cstdio> int main() { int n; long double v, ans = 0; scanf("%d", &n); for (int i = 1; i <= n; i++) { scanf("%Lf", &v); //使用long double输入输出 ans += v * i * (n + 1 - i); } printf("%.2Lf\n", ans); return 0; }