Day34

class Solution {
    private:
    int ok(vector<int> arr,int pages)
    {
        int cnt=1,curr=0;
        for(int i:arr)
        {
            if(curr+i<=pages)
            {
                curr+=i;
            }
            else
            {
                cnt++;
                curr=i;
            }
        }
        return cnt;
    }
  public:
    int findPages(vector<int> &arr, int k) {
        // code here
        int n=arr.size();
        if(n<k) return -1;
        if(k==1) return accumulate(arr.begin(),arr.end(),0);
        int l=*max_element(arr.begin(),arr.end());
        int h=accumulate(arr.begin(),arr.end(),0);
        int ans=INT_MAX;
        while(l<=h)
        {
            int m=l+(h-l)/2;
            int s=ok(arr,m);
            if(s<=k)
            {
                ans=min(ans,m);
                h=m-1;
            }
            else
            {
              l=m+1;
            }
            
        }
        return ans==INT_MAX?-1:ans;
    }
};