timecomplexity

Question

for(int i=0; i<n; i++)
    for(int j=i+1; j<n; j++)
        for(int k=j+1; k<n; k++)

Comments

please solve this question

Answer 1

Counting the number of times the inner most loop gets executed equals, 

n-2 + n-3 + n-2 + ....1
+n-3 + n-2 + .... + 1
+
...
+ 3 + 2 + 1

= (n-2)(n-1)/2 + (n-3)(n-2)/2 + ... + 3*4/2

= (n² - 3n + 2 + n² - 5n + 6 + .... )/2

= O(n³) as there are n terms and n² is the dominating term in each of them. 

Answer 2

This should be O(n^3) as for each iteration of outer loop inner loop runs O(n^2) time and outer loop runs O(n) time

Answer 3

https://gateoverflow.in/1920/gate2014-1_42