XTU 1250

http://202.197.224.59/OnlineJudge2/index.php/Problem/read/id/1250

Super Fast Fourier Transform

Bobo has two sequences of integers {a1,a2,…,an} and {b1,b2,…,bm}. He would like to find

∑i=1n∑j=1m⌊|ai−bj|−−−−−−−√⌋.

Note that ⌊x⌋ denotes the maximum integer does not exceed x, and |x| denotes the absolute value of x.

Input

The input contains at most 30 sets. For each set:

The first line contains 2 integers n,m (1≤n,m≤105).

The second line contains n integers a1,a2,…,an.

The thrid line contains m integers b1,b2,…,bm.

(ai,bi≥0,a1+a2+⋯+an,b1+b2+…,bm≤106)

Output

For each set, an integer denotes the sum.

Sample Input

1 2
1
2 3
2 3
1 2
3 4 5

Sample Output

2
7

不得不说自己笨，这么简单，当时就是不会

题意：n个a,m个b的相乘的累积和

思路：把重复的a和b找出了，会减少很大的复杂度

#include <stdio.h>
#include <math.h>
#include <string.h>
#include <stdlib.h>

int a[100005],b[100005],suma[1000005],sumb[1000005];
long long ans;

int main()
{
    int m,n,acut,bcut,tmp;
    while(~scanf("%d%d",&m,&n))
    {
        acut = 0,bcut = 0;
        memset(suma,0,sizeof(suma));
        memset(sumb,0,sizeof(sumb));
        for(int i = 1;i<=m;i++)
        {
            scanf("%d",&tmp);
            if(suma[tmp]==0)
                a[acut++] = tmp;
            suma[tmp]++;
        }
        for(int i = 1;i<=n;i++)
        {
            scanf("%d",&tmp);
            if(sumb[tmp]==0)
                b[bcut++] = tmp;
            sumb[tmp]++;
        }
        ans = 0;
        for(int i = 0;i<acut;i++)
            for(int j = 0;j<bcut;j++)
            {
                ans+=(long long ) suma[a[i]]*sumb[b[j]]*(long long )(sqrt(abs(a[i]-b[j])));
            }
        printf("%lld
",ans);
    }
    return 0;
}