https://leetcode.com/problems/perfect-squares/

perfect_squares.go

func numSquares(n int) int {
    // we are going to keep the minumum number of squares required to get the corresponding number
    // index here represents the desire number
    nums := make([]int, n + 1)
    
    // we calculate the minumum number of squares for each number from 1 to n
    for i := 1; i <= n; i++ {
        // as we have to get the minumum, at the first step we use INF as undefined number
        num := (1 << 31) - 1
        
        // here we walk through the list of squares up to the current number
        for j := 1; j * j <= i; j++ {
            square := j * j
            // min_number = min(current_number - square + 1, min_number)
            num = min(num, nums[i - square] + 1)
        }
        
        nums[i] = num
    }
  
    return nums[n]
}

func min(a, b int) int {
    if a < b {
        return a
    }
    
    return b
}