ELFhash字符串散列函数——HDU1004

最新推荐文章于 2020-11-17 00:02:14 发布

最新推荐文章于 2020-11-17 00:02:14 发布 · 103 阅读

本文介绍了一个用于统计编程比赛中每种颜色气球数量的程序。该程序使用 ELF 散列算法来处理多种颜色的气球输入，并找出最受欢迎的问题所对应的气球颜色。

Problem Description

Contest time again! How excited it is to see balloons floating around. But to tell you a secret, the judges' favorite time is guessing the most popular problem. When the contest is over, they will count the balloons of each color and find the result.

This year, they decide to leave this lovely job to you.

Input

Input contains multiple test cases. Each test case starts with a number N (0 < N <= 1000) -- the total number of balloons distributed. The next N lines contain one color each. The color of a balloon is a string of up to 15 lower-case letters.

A test case with N = 0 terminates the input and this test case is not to be processed.

Output

For each case, print the color of balloon for the most popular problem on a single line. It is guaranteed that there is a unique solution for each test case.

Sample Input

5

green

red

blue

red

red

3

pink

orange

pink

0

Sample Output

red

pink

#include <iostream>
#include <cstring>
using namespace std;

#define table_size 10000

int ELFhash(char* key, long M) {
	unsigned long h = 0;
	while(*key) {
		h = (h << 4) + *key++;
		unsigned long g = h & 0xF0000000L;
		if (g) h ^= g >> 24;
		h &= ~g;
	}
	return h % M;
}


int main(){
	char key[15];
	int cnt,n;
	while(cin >> n){
		if(!n) break;
		cnt = n;
		int table[table_size] = {0};
		char color[15];
		int max = 0;
		int hash;
		while(cnt--){
			cin >> key;
			hash = ELFhash(key, table_size);
			++table[hash];
			if(table[hash] > max){
				max = table[hash];
				strcpy(color, key);
			}
		}
		cout << color << endl;
	}
	return 0;
}