#include<bits/stdc++.h>
using namespace std;
#define int long long
inline int read()
{
    int x=0,f=1;
    char ch=getchar();
    while(ch<'0'||ch>'9')
    {
        if(ch=='-')
            f=-1;
        ch=getchar();
    }
    while(ch>='0' && ch<='9')
        x=x*10+ch-'0',ch=getchar();
    return x*f;
}
void write(int x)
{
    if(x<0)
        putchar('-'),x=-x;
    if(x>9)
        write(x/10);
    putchar(x%10+'0');
    return;
}
const int maxN = 1E5;
int n,m,a[maxN+10];
bool ch(int n){
	int set_sum=0,section=0;
	for(int i=1;i<=n;++i){
		if(a[i]+set_sum>n) { set_sum=a[i]; ++section; }
		else set_sum+=a[i];
	}
	return 1-(section<m);
}
int l,r,md;
signed main(){
	n=read(); m=read();
	for(int i=1;i<=n;++i) { a[i]=read(); l+=(a[i]-l)*(a[i]>l); r+=a[i]; }
	while(l<=r){
		md=l+(r-l>>1);
		if(ch(md)) l=md+1;
		else r=md-1;
	}
	write(l);
	return 0;
}

re on 2345 求助，感谢