B - Binary Search Aizu - ALDS1_4_B

2-Day2-B
Search II
You are given a sequence of n integers S and a sequence of different q integers T. Write a program which outputs C, the number of integers in T which are also in the set S.

Input
In the first line n is given. In the second line, n integers are given. In the third line q is given. Then, in the fourth line, q integers are given.

Output
Print C in a line.

Constraints
Elements in S is sorted in ascending order
n ≤ 100000
q ≤ 50000
0 ≤ an element in S ≤ 109
0 ≤ an element in T ≤ 109
Sample Input 1
5
1 2 3 4 5
3
3 4 1
Sample Output 1
3
Sample Input 2
3
1 2 3
1
5
Sample Output 2
0
Sample Input 3
5
1 1 2 2 3
2
1 2
Sample Output 3
2
Notes

题意：
给定一个n个整数的序列S和一个不同q个整数的序列T。写一个程序，输出C，T中的整数数，也在集合S中。

思路：看见他的题目名没。二分查找binary_search()就完了。

代码如下：

#include<cstdio>
#include<queue>
#include<cmath>
#include<cstring>
#include<iostream>
#include<algorithm>
using namespace std;

int main(void)
{
    int ss[100001],qs,sum=0;
    int s;
    cin>>s;
    for(int i=0;i<s;i++)
    cin>>ss[i];
    int q;
    cin>>q;
    for(int i=0;i<q;i++)
    {
        cin>>qs;
        if(binary_search(ss,ss+s,qs))
        sum++;
    }
    cout<<sum<<endl;

}