#801
Minimum Swaps To Make Sequences Increasing
HardArrayDynamic ProgrammingDynamic ProgrammingArray
Approaches
Brute ForceOptimal
Complexity Comparison
| Brute Force | Optimal Solution★ | |
|---|---|---|
| Time | O(n²) | O(n) |
| Space | O(1) | O(1) |
💡
Intuition
Time O(n)Space O(1)
The optimal approach uses dynamic programming to keep track of the minimum swaps needed to make both sequences strictly increasing. This is efficient and avoids unnecessary checks.
⚙️
Algorithm
4 steps- 1Step 1: Initialize two variables to track the minimum swaps needed without and with a swap.
- 2Step 2: Iterate through both arrays, updating the swap counts based on the previous states.
- 3Step 3: Use conditions to decide whether to swap or not based on the increasing order.
- 4Step 4: Return the minimum swaps needed.
solution.py18 lines
1# Full working Python code
2
3def min_swaps(nums1, nums2):
4 n = len(nums1)
5 no_swap = 0
6 swap = 1
7 for i in range(1, n):
8 no_swap_temp = no_swap
9 swap_temp = swap
10 if nums1[i] > nums1[i - 1] and nums2[i] > nums2[i - 1]:
11 no_swap_temp = min(no_swap_temp, no_swap)
12 swap_temp = min(swap_temp, swap + 1)
13 if nums1[i] > nums2[i - 1] and nums2[i] > nums1[i - 1]:
14 no_swap_temp = min(no_swap_temp, swap)
15 swap_temp = min(swap_temp, no_swap + 1)
16 no_swap, swap = no_swap_temp, swap_temp
17 return min(no_swap, swap)
18ℹ
Complexity note: This complexity is linear because we only go through the arrays once, updating our swap counts based on previous states.
- 1Understanding the conditions for strict increase is crucial.
- 2Dynamic programming can significantly reduce the number of checks needed.
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