爱站程序员基地For this problem an A-sequence is a sequence of positive integers ai satisfying 1 ≤ a1 < a2 < a3 < . . .and every ak of the sequence is not the sum of two or more distinct earlier terms of the sequence. You should write a program to determine if a given sequence it is or it is not an A-sequence.
Input
The input consists of a set of lines, each line starts with an integer 2 ≤ D ≤ 30 that indicates the number of integers that the current sequence has. Following this number there is the sequence itself. The sequence is composed by integers, each integer is greater than or equal to 1 and less than or equal to 1000. The input is terminated by enf of file (EOF).
Output
For each test case in the input you should print two lines: the first line should indicate the number of the test case and the test case itself; in the the second line you should print ‘This is an A-sequence.’, if the corresponding test case is an A-sequence or ‘This is not an A-sequence.’, if the corresponding test case is not an A-sequence.
Sample Input
2 1 2
3 1 2 3
10 1 3 16 19 25 70 100 243 245 306
Sample Output
Case #1: 1 2
This is an A-sequence.
Case #2: 1 2 3
This is not an A-sequence.
Case #3: 1 3 16 19 25 70 100 243 245 306
This is not an A-sequence.
题目大意：序列中任意多个的和是否存在与序列中(自己本身除外)
#include <iostream>#include <cstring>using namespace std;const int N = 30010, M = 35;int a[M];int cnt[N];int n, s = 0;int main(){while(~scanf(\"%d\", &n)){int sum = 0;for(int i = 0; i < n; i ++ ){scanf(\"%d\", &a[i]);sum += a[i];}bool flag = true;for(int i = 1; i < n && flag; i ++ )if(a[i - 1] > a[i] || a[i - 1] < 1 || a[i] < 1)flag = false;if(flag){memset(cnt, 0, sizeof cnt);cnt[0] = 1;//首先是存储它们本身for(int i = 0; i < n; i ++ ){if(cnt[a[i]]){flag = false;break;}/*1.由于前面判断flag是否为0，那么用cnt[i]来存储是否有子序列(不一定连续)的和为i。2.cnt[i]如果存在子序列的和为i，那么cnt[i] = 1;否则为03.把cnt[0] = 1默认自己算子序列的和，但是再A序列中是符合要求的我们通过cnt[0] = 1, 先求出它们本身，其次可以求出序列中任意多个数的和！*/for(int j = sum; j >= a[i]; j -- )if(cnt[j - a[i]])cnt[j] = 1;}}printf(\"Case #%d:\", ++ s);for(int i = 0; i < n; i ++ )printf(\" %d \", a[i]);printf(\"\\nThis is %san A-sequence.\\n\", flag ? \"\" : \"not \");}return 0;}
