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 · 85 阅读

本文介绍了一个用于统计编程比赛中各题目受欢迎程度的程序。通过读取输入的颜色字符串并使用ELF哈希算法来记录每种颜色出现的次数，最终输出出现次数最多的颜色。此程序能够处理多个测试案例。

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;
}