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.
题目的意思是问你能不能在n个数里面选若干个相加使得它们的和能整除m,显然当n>=m时肯定可以,那么当n<m时可以利用dp来做
dp[i][j]表示用前i-1个数的sum值得到j(这里j=(sum%m)),显然状态转移方程为 dp[i+1][(j+a[i])%m] = 1,或者 dp[i+1][j];
1 #include <cstdio> 2 #include <cstring> 3 #include <iostream> 4 #include <queue> 5 #include <vector> 6 #include <stack> 7 8 using namespace std; 9 10 const int M = 10005; 11 const int maxn = 1100000; 12 typedef long long ll; 13 14 vector<int>G[maxn]; 15 queue<int>Q; 16 stack<int>st; 17 18 priority_queue<int>q; 19 20 21 int l[maxn],r[maxn]; 22 int a[maxn]; 23 int dp[1005][1005]; 24 int main() 25 { 26 27 int n; 28 int ans = 0; 29 int m; 30 scanf("%d%d",&n,&m); 31 for(int i=1;i<=n;i++){ 32 scanf("%d",&a[i]); 33 34 } 35 36 if(n>=m){ 37 printf("YES "); 38 } 39 else { 40 41 for(int i=1;i<=n;i++){ 42 dp[i][a[i]%m] = 1; 43 for(int j=0;j<m;j++){ 44 if(dp[i-1][j]){ 45 dp[i][(j+a[i])%m] = 1; 46 dp[i][j] = 1; 47 } 48 } 49 } 50 if(dp[n][0])printf("YES "); 51 else printf("NO "); 52 } 53 54 55 56 return 0; 57 }