10642 - Can You Solve It?

Difficulty : easy

Solution Description :

Math problem

This problem is the reverse process of problem 880 - Cantor Fractions
So first see the hints of problem 800 - Cantor Fractions

In 880: down = (m - up) + 1
Here up = (m - down) + 1
      => m = up + down - 1 --------------------------------------(i)
so,  =>max = m*(m+1)/2      ----------------------------------(ii)
In 880: up = (max - n) + 1
Here down = (max - n) + 1
      => n = max - down + 1 ------------------------------------(iii)

Input: up1 down1 up2 down2
increment all value i.e. up1++, down1++, up2++, down2++
using equation (i),(ii), and (iii) you can got n1 and n2

print n2-n1

Use long long data type in c for all calculation