Next Smaller Permutation - Facebook Top Interview Questions
Problem Statement :
You are given a list of integers nums. Given that you must first swap any two numbers in nums, return the lexicographically largest list which is smaller than nums. If there is no solution, then return the same list. Constraints n ≤ 100,000 where n is the length of nums Example 1 Input nums = [2, 0, 1] Output [1, 0, 2] Explanation The largest permutation we can make that's less than nums is [1, 0, 2]. We swap 2 and 1. Note that [1, 2, 0] is not possible since getting this permutation requires 2 swaps. Example 2 Input nums = [1, 2, 3] Output [1, 2, 3] Explanation There's no way to get a smaller permutation so we return the same list.
Solution :
Solution in C++ :
vector<int> solve(vector<int>& nums) {
int i, j;
for (i = nums.size() - 2; i >= 0; i--) {
if (nums[i] > nums[i + 1]) break;
}
if (i < 0) return nums;
for (j = nums.size() - 1; j >= 0; j--) {
if (j > 0 && nums[j] == nums[j - 1]) continue;
if (nums[j] < nums[i]) break;
}
swap(nums[i], nums[j]);
return nums;
}
Solution in Python :
class Solution:
def solve(self, nums):
nums_len = len(nums)
for i in range(nums_len - 2, -1, -1):
if nums[i] <= nums[i + 1]:
continue
pos = i + 1
swap_pos = None
while pos < nums_len and nums[pos] < nums[i]:
if not swap_pos or nums[pos] > nums[pos - 1]:
swap_pos = pos
pos += 1
nums[i], nums[swap_pos] = nums[swap_pos], nums[i]
return nums
return nums
View More Similar Problems
Mr. X and His Shots
A cricket match is going to be held. The field is represented by a 1D plane. A cricketer, Mr. X has N favorite shots. Each shot has a particular range. The range of the ith shot is from Ai to Bi. That means his favorite shot can be anywhere in this range. Each player on the opposite team can field only in a particular range. Player i can field from Ci to Di. You are given the N favorite shots of M
View Solution →Jim and the Skyscrapers
Jim has invented a new flying object called HZ42. HZ42 is like a broom and can only fly horizontally, independent of the environment. One day, Jim started his flight from Dubai's highest skyscraper, traveled some distance and landed on another skyscraper of same height! So much fun! But unfortunately, new skyscrapers have been built recently. Let us describe the problem in one dimensional space
View Solution →Palindromic Subsets
Consider a lowercase English alphabetic letter character denoted by c. A shift operation on some c turns it into the next letter in the alphabet. For example, and ,shift(a) = b , shift(e) = f, shift(z) = a . Given a zero-indexed string, s, of n lowercase letters, perform q queries on s where each query takes one of the following two forms: 1 i j t: All letters in the inclusive range from i t
View Solution →Counting On a Tree
Taylor loves trees, and this new challenge has him stumped! Consider a tree, t, consisting of n nodes. Each node is numbered from 1 to n, and each node i has an integer, ci, attached to it. A query on tree t takes the form w x y z. To process a query, you must print the count of ordered pairs of integers ( i , j ) such that the following four conditions are all satisfied: the path from n
View Solution →Polynomial Division
Consider a sequence, c0, c1, . . . , cn-1 , and a polynomial of degree 1 defined as Q(x ) = a * x + b. You must perform q queries on the sequence, where each query is one of the following two types: 1 i x: Replace ci with x. 2 l r: Consider the polynomial and determine whether is divisible by over the field , where . In other words, check if there exists a polynomial with integer coefficie
View Solution →Costly Intervals
Given an array, your goal is to find, for each element, the largest subarray containing it whose cost is at least k. Specifically, let A = [A1, A2, . . . , An ] be an array of length n, and let be the subarray from index l to index r. Also, Let MAX( l, r ) be the largest number in Al. . . r. Let MIN( l, r ) be the smallest number in Al . . .r . Let OR( l , r ) be the bitwise OR of the
View Solution →