Description
https://leetcode.com/problems/perfect-squares/
Given an integer n, return the least number of perfect square numbers that sum to n.
A perfect square is an integer that is the square of an integer; in other words, it is the product of some integer with itself. For example, 1, 4, 9, and 16 are perfect squares while 3 and 11 are not.
Example 1:
Input: n = 12 Output: 3 Explanation: 12 = 4 + 4 + 4.
Example 2:
Input: n = 13 Output: 2 Explanation: 13 = 4 + 9.
Constraints:
1 <= n <= 104
Explanation
Dynamic programming dp[i] means what is the minimum number of square numbers to add up to equal to i.
Python Solution
class Solution:
def numSquares(self, n: int) -> int:
square_nums = [i**2 for i in range(0, int(sqrt(n)) + 1)]
dp = [float('inf')] * (n + 1)
dp[0] = 0
for i in range(1, n + 1):
for square in square_nums:
if i < square:
break
dp[i] = min(dp[i], dp[i - square] + 1)
return dp[n]- Time Complexity: O(N).
- Space Complexity: O(N).
where Q is the length of queries and N is the length of colors.
I found this solution very popular and helpful: https://www.youtube.com/watch?v=QzU9oKjT1bo&ab_channel=EricProgramming