题目链接:
time limit per test
2 secondsmemory limit per test
256 megabytesinput
standard inputoutput
standard outputYou 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.
Input
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).
Output
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.
Examples
input
3 5
1 2 3
output
YES
input
1 6
5
output
NO
input
4 6
3 1 1 3
output
YES
input
6 6
5 5 5 5 5 5
output
YES
题意:
能否找到一个子序列的和能被m整除;
思路:
有一道hdu的水题就是这样的,以前傻傻的居然不会做;就是把余数拿出来搞搞就好了;
AC代码:
#include <iostream> #include <cstdio> #include <cstring> #include <algorithm> #include <cmath> #include <bits/stdc++.h> #include <stack> #include <map> using namespace std; #define For(i,j,n) for(int i=j;i<=n;i++) #define mst(ss,b) memset(ss,b,sizeof(ss)); typedef long long LL; template<class T> void read(T&num) { char CH; bool F=false; for(CH=getchar();CH<'0'||CH>'9';F= CH=='-',CH=getchar()); for(num=0;CH>='0'&&CH<='9';num=num*10+CH-'0',CH=getchar()); F && (num=-num); } int stk[70], tp; template<class T> inline void print(T p) { if(!p) { puts("0"); return; } while(p) stk[++ tp] = p%10, p/=10; while(tp) putchar(stk[tp--] + '0'); putchar(' '); } const int mod=1e9+7; const double PI=acos(-1.0); const int inf=1e9; const int N=1e6+20; const int maxn=1e3+110; const double eps=1e-12; int n,m,a[N],vis[maxn],temp[maxn]; int main() { read(n);read(m); int flag=0; For(i,1,n)read(a[i]); vis[0]=1; For(i,1,n) { a[i]%=m; int t=(m-a[i])%m; if(vis[t]){flag=1;break;} mst(temp,0); for(int j=0;j<m;j++) { if(vis[j])temp[(j+a[i])%m]=1; } for(int j=0;j<m;j++) if(temp[j])vis[j]=1; } if(flag)cout<<"YES "; else cout<<"NO "; return 0; }