哈希算法：Sort

 

 

如果用sort函数的话需要nlogn的时间复杂度

#include<algorithm>
#include<string.h>
#include<iostream>
#include<stdio.h>
#include<string.h>
#define OFFSET 500000 
int Hash[1000001];
int main()
{
    int n, m;
    while (scanf_s("%d%d", &n, &m) != EOF)
    {
        for (int i = -500000; i <= 500000; i++)
            Hash[i + OFFSET] = 0;
        for (int i = 1; i <= n; i++)
        {
            int x;
            scanf_s("%d", &x);
            Hash[x + OFFSET] = 1;
        }
        for (int i = 500000; i >= -500000; i--)
        {
            if (Hash[i + OFFSET] == 1)
            {
                printf("%d", i);
                m--;
                if (m != 0)
                    printf(" ");
                else
                {
                    printf("\n");
                    break;
                }
            }
        }

    }
    return 0;
}