【HDOJ】1800 Flying to the Mars

1. 题目描述
挺简单的一道题，给定$n$个大整数，求出现最多的次数。

2. 基本思路
这题是可以使用哈希做，ELFHash等哈希都可以过。

3. 代码

/* 1800 */
#include <iostream>
#include <sstream>
#include <string>
#include <map>
#include <queue>
#include <set>
#include <stack>
#include <vector>
#include <deque>
#include <bitset>
#include <algorithm>
#include <cstdio>
#include <cmath>
#include <ctime>
#include <cstring>
#include <climits>
#include <cctype>
#include <cassert>
#include <functional>
#include <iterator>
#include <iomanip>
using namespace std;
//#pragma comment(linker,"/STACK:102400000,1024000")

#define sti                set<int>
#define stpii            set<pair<int, int> >
#define mpii            map<int,int>
#define vi                vector<int>
#define pii                pair<int,int>
#define vpii            vector<pair<int,int> >
#define rep(i, a, n)     for (int i=a;i<n;++i)
#define per(i, a, n)     for (int i=n-1;i>=a;--i)
#define clr                clear
#define pb                 push_back
#define mp                 make_pair
#define fir                first
#define sec                second
#define all(x)             (x).begin(),(x).end()
#define SZ(x)             ((int)(x).size())
#define lson            l, mid, rt<<1
#define rson            mid+1, r, rt<<1|1

const int maxl = 105;
const int MOD = 7003;
int H[MOD], cnt[MOD];
char s[maxl];
int n, ans;

inline int ELFHash(char *s) {
    unsigned int h = 0;
    unsigned int g;
    int i = 0;

    while (s[i]) {
        h = (h<<4) + s[i];
        g = h & 0xf0000000L;
        if (g) {
            h ^= (g >> 24);
            h &= ~g;
        }
        ++i;
    }

    return h & 0x7fffffff;
}

inline void Hash(char *s) {
    int i = 0;

    while (s[i]=='0')    ++i;
    int k = ELFHash(s+i);
    int t = k % MOD;

    while (H[t]!=-1 && H[t]!=k)
        t = (t + 10) % MOD;

    if (H[t] == -1) {
        cnt[t] = 1;
        H[t] = k;
    } else if (++cnt[t] > ans) {
        ans = cnt[t];
    }
}

int main() {
    ios::sync_with_stdio(false);
    #ifndef ONLINE_JUDGE
        freopen("data.in", "r", stdin);
        freopen("data.out", "w", stdout);
    #endif

    while (scanf("%d",&n)!=EOF) {
        memset(H, -1, sizeof(H));
        ans = 1;
        rep(i, 0, n) {
            scanf("%s", s);
            Hash(s);
        }
        printf("%d
", ans);
    }

    #ifndef ONLINE_JUDGE
        printf("time = %d.
", (int)clock());
    #endif

    return 0;
}