#UVa：11849－CD

比較兩個已排序的序列其共同的部分有多少即可得解。

C++(0.470)

/*******************************************************/
/* UVa 11849 CD                                        */
/* Author: Maplewing [at] knightzone.studio            */
/* Version: 2018/05/14                                 */
/*******************************************************/
#include <iostream>
#include <cstdio>
#include <vector>
using namespace std;

int main(){
  int N, M;
  while (scanf("%d%d", &N, &M) != EOF &&
       N != 0 && M != 0){
    vector<int> nCDs(N, 0);
    vector<int> mCDs(M, 0);

    for (int i = 0 ; i < N ; ++i ){
      scanf("%d", &nCDs[i]);
    }

    for (int i = 0 ; i < M ; ++i ){
      scanf("%d", &mCDs[i]);
    }

    int bothOwnCount = 0;
    for (int i = 0, j = 0 ; i < N && j < M ; ){
      if(nCDs[i] == mCDs[j]){
        ++bothOwnCount;
        ++i;
        ++j;
      }
      else if(nCDs[i] > mCDs[j]) ++j;
      else ++i;
    }

    printf("%d\n", bothOwnCount);
  }
  return 0;
}