题解

#include<bits/stdc++.h>
using namespace std; 
int n,m,mid,l,r,ma,a[1000005];
bool judge(int x)
{
    long long s=0,k=1;
    for(int i=1;i<=n;i++)
        if(s+a[i]<=x) s+=a[i];
    else s=a[i],k++;
    return k<=m;
}
int main(){
    cin>>n>>m;
    for(int i=1;i<=n;i++) cin>>a[i],ma=max(ma,a[i]);
    l=ma;r=1e9;
    mid=l+r>>1;
    while(l<r)
        {
            if(judge(mid)) r=mid;
            else l=mid+1;
            mid=l+r>>1;
            
        }
    cout<<l;
	return 0;
}