Next Permutation

The next permutation question is a leetcode question that is works on finding the next lexogaphically greater permutation combination ** When does the permutation changes? or increase? it increases when a number on the left is smaller than a number on the right let the given array be arr = [ 1 , 2 , 3 ] the next permutation in sorted way are [ 1 , 2 , 3 ] [ 1 , 3 , 2 ] [ 2 , 1 , 3 ] [ 2 , 3 , 1 ] [ 3 , 1 , 2 ] [ 3 , 2 , 1 ] so when the question is What is the next permutation of [2,1,3]?, the answer will be [2,3,1] Approach to the solve the question Find first decreasing element from right → swap → reverse the rest this way we find the next permutation arr = [1, 3, 5, 4, 2] Step 1 : to find where there is change when we * look right to left * 2<4 4<5 but 3 > 5 so this is where we can make the array slighly greater step 2: make the array slighly greater so we find element in right of 3 ** **smallest number greater than 3 so we swap with element 4 swap 3 and 4 -> [1,4,5,3,2] step 3: reve