<p>Given an integer <code>n</code>, return <em>the least number of perfect square numbers that sum to</em> <code>n</code>.</p>

<p>A <strong>perfect square</strong> is an integer that is the square of an integer; in other words, it is the product of some integer with itself. For example, <code>1</code>, <code>4</code>, <code>9</code>, and <code>16</code> are perfect squares while <code>3</code> and <code>11</code> are not.</p>

<p>&nbsp;</p>
<p><strong class="example">Example 1:</strong></p>

<pre>
<strong>Input:</strong> n = 12
<strong>Output:</strong> 3
<strong>Explanation:</strong> 12 = 4 + 4 + 4.
</pre>

<p><strong class="example">Example 2:</strong></p>

<pre>
<strong>Input:</strong> n = 13
<strong>Output:</strong> 2
<strong>Explanation:</strong> 13 = 4 + 9.
</pre>

<p>&nbsp;</p>
<p><strong>Constraints:</strong></p>

<ul>
	<li><code>1 &lt;= n &lt;= 10<sup>4</sup></code></li>
</ul>

class Solution {
public:
    int solve(int num , vector<int>& dp , vector<int>& nums){
        if(num==0){
            return 0;
        }
        if(dp[num]!=-1){
            return dp[num];
        }
        int ans = INT_MAX;
        for(int i=0 ; i<nums.size() ;i++){
            if (nums[i]<=num) ans = min(ans , 1+solve(num-nums[i] , dp , nums));
            else{
                break;
            }
        }
        return dp[num] = ans;
    }
    int numSquares(int n) {
        vector<int> nums;
        for(int i=1 ; i<= 1e4 ; i++){
            nums.push_back(i*i);
        }
        vector<int> dp((int)1e4+5 , -1 );
        return solve(n , dp , nums);
    }
};
100901