题解

#include <iostream>
#include <cmath>
#include <string>
#include <cstring>
#include <iomanip>
#include <algorithm>
#include <vector>
#include <cstdio>
#define int long long
using namespace std;
const int N=1e5+3,M=2e5+3,inf=2147483647;
int n,m,cnta,cntb;
int a[N],b[N],c[M];
bool cmp(int a,int b){
return a>b;
}
signed main(){
scanf("%lld %lld",&n,&m);
for(int i=1;i<=n;i++){
scanf("%lld",&a[i]);
cnta+=a[i];
}
for(int i=1;i<=m;i++)scanf("%lld",&b[i]);
for(int i=1;i<=n;i++)c[i]=a[i];
for(int i=1;i<=m;i++)c[n+i]=b[i];
sort(c+1,c+1+n+m,cmp);
for(int i=1;i<=n;i++)cntb+=c[i];
if(b[m]<c[n]){
cntb-=c[n];
cntb+=b[m];
}
printf("%lld\n",cntb); 
return 0;
}