Leetcode•Apr 29, 2025
Perfect Squares
Hazrat Ali
Leetcode
Given an integer n, return the least number of perfect square numbers that sum to n.
A 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, 1, 4, 9, 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.
Solution
/**
* @param {number} n
* @return {number}
*/
const numSquares = n => {
if (n <= 0) {
return 0;
}
const dp = Array(n + 1).fill(0);
for (let i = 1; i <= n; i++) {
dp[i] = Number.MAX_SAFE_INTEGER;
for (let j = 1; j * j <= i; j++) {
dp[i] = Math.min(dp[i], dp[i - j * j] + 1);
}
}
return dp[n];
};