题解

#include<iostream>
#include<cmath>
using namespace std;
int main(){
    int n,k,w[200010],big=0;
    cin>>n>>k;
    long long sum=0;
    for(int i=0;i<n;i++){
        cin>>w[i];
        sum+=w[i];
        big=max(big,w[i]);
    }
    long long l=big,r=sum,min=sum;
    while(l<=r){
        long long mid=(l+r)/2,sum=0;
        int cnt=1;
        bool flag=1;
        for(int i=0;i<n;i++){
            if(w[i]>mid){
                flag=0;
                break;
            }
            if(sum+w[i]>mid){
                cnt++;
                sum=w[i];
            }else{
                sum+=w[i];
            }
        }
        if(flag!=0&&cnt<=k){
            min=mid;
            r=mid-1;
        }else{
            l=mid+1;
        }
    }
    cout<<min;
    return 0;
}