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leetcode 279 solution

 279Perfect Squares

Perfect Squares leetcode


Given an integer n, return the least number of perfect square numbers that sum to n.

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, 149, 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


solution:

class Solution {
public:
    int numSquares(int n) {
        //vector for updating the dp array/values
        vector<int> dp(n+1,INT_MAX);
        //base case
        dp[0]=0;
        int count = 1;
        while(count*count <= n) {
        int sq = count*count;
        for(int i = sq; i < n+1; i++) {
            dp[i] = min(dp[i-sq] + 1,dp[i]);
        }
        count++;
    }
    return dp[n];
    }
};


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