B. Modulo Sum
You are given a sequence of numbers a1, a2, ..., an, and a number m.
Check if it is possible to choose a non-empty subsequence aij such that the sum of numbers in this subsequence is divisible by m.
The first line contains two numbers, n and m (1 ≤ n ≤ 106, 2 ≤ m ≤ 103) — the size of the original sequence and the number such that sum should be divisible by it.
The second line contains n integers a1, a2, ..., an (0 ≤ ai ≤ 109).
In the single line print either "YES" (without the quotes) if there exists the sought subsequence, or "NO" (without the quotes), if such subsequence doesn't exist.
3 5
1 2 3
YES
1 6
5
NO
4 6
3 1 1 3
YES
6 6
5 5 5 5 5 5
YES
In the first sample test you can choose numbers 2 and 3, the sum of which is divisible by 5.
In the second sample test the single non-empty subsequence of numbers is a single number 5. Number 5 is not divisible by 6, that is, the sought subsequence doesn't exist.
In the third sample test you need to choose two numbers 3 on the ends.
In the fourth sample test you can take the whole subsequence.
1 #include<cstdio> 2 #include<vector> 3 #include<cmath> 4 #include<queue> 5 #include<map> 6 #include<cstring> 7 #include<algorithm> 8 using namespace std; 9 typedef long long ll; 10 typedef unsigned long long ull; 11 const int maxn=1e3+5; 12 bool vis[maxn],sum[maxn]; 13 vector<int>sum_id; 14 int main() 15 { 16 int n,m; 17 scanf("%d%d",&n,&m); 18 if(n>m) 19 { 20 puts("YES"); 21 return 0; 22 } 23 for(int i=0;i<n;i++) 24 { 25 int tt; 26 scanf("%d",&tt); 27 tt%=m; 28 if(!tt) 29 { 30 puts("YES"); 31 return 0; 32 } 33 int num=sum_id.size(); 34 for(int j=0;j<num;j++) 35 { 36 int newsum=(sum_id[j]+tt)%m; 37 if(newsum==0){puts("YES");return 0;}; 38 if(!vis[newsum])vis[newsum]=1,sum_id.push_back(newsum); 39 } 40 if(!vis[tt])vis[tt]=1,sum_id.push_back(tt); 41 } 42 puts("NO"); 43 return 0; 44 }