hdu 1029（hash）

#include <algorithm>
#include <cstdio>
#include <cstring>
#define N 1000010
#define inf 0x3f3f3f3f
using namespace std;
const int HASH=1000007;
const int MAXN=1000010;
struct HASHMAP
{
    int head[HASH],next[MAXN],size;
    int state[MAXN],num[MAXN];
    void init()
    {
        size=0;
        memset(head,-1,sizeof(head));
        memset(num,0,sizeof(num));
    }
    int insert(int val)
    {
        int h=(val%HASH+HASH)%HASH;
        for(int i=head[h];~i;i=next[i])
        {
            if(val==state[i])
            {
                num[i]++;
                return num[i];
            }
        }
        state[size]=val;
        num[size]=1;
        next[size]=head[h];
        head[h]=size++;
        return 1;
    }
}H;
int main()
{
    int n,x;
    while(scanf("%d",&n)>0)
    {
        H.init();
        int mx=0,ans=0;
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&x);
            int res=H.insert(x);
            if(res>mx)
            {
                ans=x;mx=res;
            }
        }
        printf("%d\n",ans);
    }
}