XidianOJ 1195 Industry of Orz Pandas

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
using namespace std;
typedef long long LL;

int a[20001],b[20001];
int n,m,x;
int main(){
    while (scanf("%d %d %d",&n,&m,&x) != EOF){
        int i,j,k;
        for (i=1;i<=n;i++){
            scanf("%d",&a[i]);
        }
        for (i=1;i<=m;i++){
            scanf("%d",&b[i]);
        }
        sort(a+1,a+1+n); sort(b+1,b+1+m);
        int nowa = 1,nowb = 1,total = 0;
        while (nowa <= n && nowb <= m){
            int res = a[nowa] - b[nowb];
            if (res<0) res = -res;
            if (res<=x){
                nowa ++; nowb ++; total ++; continue;
            } 
            else {
                if (a[nowa] > b[nowb]){
                    nowb++;
                }
                else {
                    nowa++;
                }
            }
        }
        printf("%d\n",total);
    }
    return 0;
}