"Leetcode" Perfect Squares

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

Topic:

Given a positive integer n, find the least number of perfect square numbers (for example, 1, 4, 9, 16, ... ) which sum to N.

For example, given n =12, return3Because12 = 4 + 4 + 4; given n =13, return2Because13 = 4 + 9.

Ideas:

N=m^2+s
m= (int) math.sqrt (n) takes the entire table down to the maximum possible total number of squares c[i] represents the recursive formula for the minimum number of complete squares that comprise I:

C[i] =1+c[s] Consider 12=3^2+3 c[12]=1+c[3]=1+3=4, but 12=4+4+4 is c[12]=3
So not m for the maximum square number will be able to get c[i], need to traverse all j<m n=j^2+k min (1+c[k])

Algorithm:

public int numsquares (int n) {      int c[] = new Int[n + 1];      for (int i = 1; I <= n; i++) {          int tmp = (int) math.sqrt (i);          C[i] = c[i-tmp * TMP] + 1;          for (int j = tmp-1; J >= 1; j--) {              tmp = J * J;              C[i] = Math.min (c[i-tmp] + 1, c[i]);          }      }      return c[n];  }  

"Leetcode" Perfect Squares