Hi!
I tried my own appraoch to this problem using binary search, before i saw the tutorial.
Even though my code seems to be working fine, im not passing the hackerblocks testcases. Please go through my appraoch ( at : https://ide.codingblocks.com/s/300779) and assist me in finding what testcase/issue i am missing.
I have used a similar appraoch with the same monotonic search space and binary search algorithm.
Thanks for yout help, it is really appreciated. 
You’re not taking input for every case.You book array is same for all the cases.I think your logic is correct.
Please see my code for better understanding.
#include<bits/stdc++.h>
using namespace std;
bool check(vectorv,int n,int m,int mid){
int curr = 0;
int count = 1;
for(int i=0;i<n;i++){
if(curr+v[i]>mid){
count++;
curr = v[i];
if(count>m){
return false;
}
}else{
curr = curr + v[i];
}
}
return true;
}
int ans(vectorv,int n,int m){
int start = v[n-1];
int sum = 0;
int ans = -1;
for(int i=0;i<n;i++){
sum = sum + v[i];
}
int end = sum;
while(start<=end){
int mid = (start+end)/2;
bool check1 = check(v,n,m,mid);
if(check1==true){
ans = mid;
end = mid - 1;
}else{
start = mid + 1;
}
}
return ans;
}
int main() {
int t;
cin>>t;
while(t–){
int n;
cin>>n;
int m;
cin>>m;
vectorv;
for(int i=0;i<n;i++){
int x;
cin>>x;
v.push_back(x);
}
cout << ans(v,n,m) << endl;
}
}