[백준] 7795번 먹을 것인가 먹힐 것인가 (C++) - binary search

문제

https://www.acmicpc.net/problem/7795

7795번: 먹을 것인가 먹힐 것인가

코드

#include <iostream>
#include <algorithm>

using namespace std;

int a[20000];
int b[20000];

int main(){
  int t,n,m;
  cin >> t;
  while(t--){
    cin >> n >> m;
    for(int i=0; i<n; i++){
      cin >> a[i];
    }
    for(int i=0; i<m; i++){
      cin >> b[i];
    }
    sort(a,a+n);
    sort(b,b+m);
    int result=0;
    for(int i=0; i<n; i++){
      int low=0;
      int high=m-1;
      int x=a[i];
      while(low<=high){
        int mid=(low+high)/2;
        if(b[mid]>=x) high=mid-1;
        else low=mid+1;
      }
      result+=low;
    }
    cout << result << '\n';
  }
  return 0;
}

정리

 

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