二的幂数组中查询范围内的乘积

// Java Stream solution
// 思路:
// 1. 找到最小数量的2的幂次表示n
// 2. 使用Java Stream API简化查询处理和乘积计算

import java.util.*;

public class SolutionStream {
    private static final int MOD = 1000000007;

    public static List<Integer> findPowers(int n) {
        List<Integer> powers = new ArrayList<>();
        int power = 1;
        while (n > 0) {
            if ((n & 1) == 1) {
                powers.add(power);
            }
            n >>= 1;
            power *= 2;
        }
        return powers;
    }

    public static int[] getQueryResults(int n, int[][] queries) {
        List<Integer> powers = findPowers(n);
        return Arrays.stream(queries)
                .mapToInt(q -> {
                    return (int) Arrays.stream(powers.subList(q[0], q[1] + 1))
                            .mapToLong(Integer::longValue)
                            .reduce(1, (a, b) -> (a * b) % MOD);
                })
                .toArray();
    }

    public static void main(String[] args) {
        int n = 15;
        int[][] queries = {{0, 1}, {2, 2}, {0, 3}};
        int[] results = getQueryResults(n, queries);
        System.out.println(Arrays.toString(results)); // 输出: [2, 4, 64]
    }
}