题解 | #最少的完全平方数#

完全背包问题，体积为n，不断往背包里面放i * i

import java.util.*;

public class Main {
    public static void main(String[] args) {
        Scanner reader = new Scanner(System.in);
        int n = reader.nextInt();
        // init
        // dp[i] = dp[i - j * j] + 1
        int[] dp = new int[n + 1];
        Arrays.fill(dp, Integer.MAX_VALUE);
        dp[0] = 0;
        for (int i = 1; i <= n; i++) {
            for (int j = 1; j <= i; j++) {
                if (j * j <= i) {
                    dp[i] = Math.min(dp[i], dp[i - j * j] + 1);
                }
            }
        }
        // 恰好体积为n
        System.out.println(dp[n]);
    }
}