I am getting wrong answer for test case 4. I am unable to find the error. I have used the functions:

binarySearchSt-returns the element equal to or less than the key

binarySearchEn-returns the element equal to or greater than the key

For every contest, I am finding the optimal v and w and then I am checking if this combination of v and w yields the minimum time.

Code:

#include<bits/stdc++.h>
using namespace std;
int binSearchSt(int a[],int len,int key){
    int l=0,h=len-1;
    while(l<=h){
        int mid=l+(h-l)/2;
        if(a[mid]==key)return a[mid];
        else if(l==h)if(mid!=0)return a[mid-1]; else return a[mid];
        else if(key<a[mid]){h=mid;}
        else l=mid+1;
    }