Unnecessary work

Technical Questions

Print all positive integer solutions to the equation

a3 + b3 = c3 + d3, (1 ≤ a, b, c, d ≤ 1000)

n = 1000

for a from 1 to n

for b from 1 to n

for c from 1 to n

for d from 1 to n

if a3 + b3 == c3 + d3

print a, b, c, d

O(N4)

n = 1000

for a from 1 to n

for b from 1 to n

for c from 1 to n

for d from 1 to n

if a3 + b3 == c3 + d3

print a, b, c, d

break

O(N4)

n = 1000

for a from 1 to n

for b from 1 to n

for c from 1 to n

d = pow(a3 + b3 - c3, 1/3)

if a3 + b3 == c3 + d3

print a, b, c, d

O(N3)

42

a3 + b3 - c3 = d3