LC 0279 [M] Perfect Squares - ALawliet/algorithms GitHub Wiki

just like Coin Change

class Solution:
    def numSquares(self, n: int) -> int:
        cache = [n] * (n + 1)
        cache[0] = 0
        
        for i in range(1, n + 1):
            for s in range(1, i + 1):
                square = s * s
                if i - square < 0:
                    break
                if 1 + cache[i - square] < cache[i]:
                    cache[i] = 1 + cache[i - square]

        return cache[n]

class Solution:
    def numSquares(self, n: int) -> int:
        dp = [n] * (n + 1)
        dp[0] = 0

        squares = [x**2 for x in range(1, n) if x**2 <= n] # passes TLE

        for target in range(1, n + 1):
            for square in squares: 
                if target - square < 0: 
                    break
                dp[target] = min(dp[target], 1+dp[target-square])
                
        return dp[n]