P1678 煩惱的高考志願（二分查找）

https://www.luogu.com.cn/problem/P1678

寫起來就很舒服 看起來就更舒服

#include<bits/stdc++.h>
using namespace std;
#define N 100005
int main(){
	int m, n, a[N], b[N], key, s = 0;
	cin >> m >> n;
	for(int i=1; i<=m; i++)
		cin >> a[i];
	sort(a+1, a+m+1);
	while(n--){
		cin >> key;
		int l=0, r=m, mid = l + ((r-l)>>1), flag = 1;
		while(l <= r && flag){
			mid = l + ((r-l)>>1);
			if(a[mid] > key)
				r = mid - 1;
			else if(a[mid] < key)
				l = mid + 1;
			else 	
				flag = 0;
		}
		if(flag){
			if(r >= 1 && l >= 1){
				if(abs(a[l] - key) < abs(a[r] - key))
					s += abs(a[l] - key);
				else
					s += abs(a[r] - key); 
			}else if(a[l] >= 1)
				s += abs(a[l] - key);
			else
				s += abs(a[r] - key); 	
		}
	}
	cout << s;
	return 0;
}