Split array largest sum

class Solution {
public:

bool find(int mid,vector<int> &a, int k){
    int painter=1;
    int area=0;
    int n=a.size();
    for(int i=0;i<n;i++){
        if(area+a[i]<=mid){
            area=area+a[i];
        }
        else{
            painter++;
            area=a[i];
            if(painter>k){
                return false;
            }
        }
    }
    return true;

}

    int splitArray(vector<int>&  a, int k) {
        int start=*max_element(a.begin(),a.end());
    int end=accumulate(a.begin(),a.end(),0);
    int ans=-1;
    while(start<=end){
        int mid=start+(end-start)/2;
        bool pos=find(mid,a,k);
        if(pos){
            ans=mid;
            end=mid-1;
        }
        else{
            start=mid+1;
        }
    }
    return ans;
    }
};