Description
One day n girls and n boys come to Xi’an to look for a mate. Each girl has a value a[i], each boy has a value b[i]. Girl i and boy j will fall in love only if a[i] + b[j] ≥ k.
Please help them make pairs as many as possible.
Input
Several test cases .
First line an integer T (1 ≤ T ≤ 10). Indicates the number of test cases.
Then T test cases follows. Each test case begins with two integer N, K (1 ≤ N ≤ 200000,0 ≤ K ≤ 109). The next line has N integers indicate a[1] to a[N] (0 ≤ a[i] ≤ 10^9). The next line has N integers indicate b[1] to b[N] (0 ≤ b[i] ≤ 10^9)
Output
For each test case, print the answer in a single line.
Sample Input
1
3 4
1 2 3
1 2 3
Sample Output
3
Code
#include <iostream>
#include <cstdio>
#include <algorithm>
using namespace std;
const int maxn=200000+10;
int a[maxn];
int b[maxn];
int main(){
int t;
cin>>t;
while(t--){
int n,k;
cin>>n>>k;
for(int i=0;i<n;i++){
scanf("%d",&a[i]);
getchar();
}
for(int i=0;i<n;i++){
scanf("%d",&b[i]);
getchar();
}
sort(a,a+n);
sort(b,b+n);
if(a[n-1]+b[n-1]<k){
printf("0\n");
continue;
}
int j=0,num=0;
for(int i=n-1;i>=0;i--){
for(;j<n;j++){
if(a[j]+b[i]==k){
num++;
j=j+1;
break;
}
}
}
printf("%d\n",num);
}
return 0;
}