快手2018春招后端笔试题解

计算(x^y)%N

package kuaishou.demo1;

import java.util.Scanner;

public class Main {

    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        long x = sc.nextLong(), y = sc.nextLong(), N = sc.nextLong();
        long res = 1;
        x = x % N;

        while (y > 0) {
            if (y % 2 == 1)
                res = (res * x) % N;
            y /= 2;
            x = (x * x) % N;
        }
        System.out.println(res);
    }
}

二分查找

package kuaishou.demo2;

import java.util.Scanner;

public class Main {
    public static void main(String[] args) {
        Scanner sc = new Scanner(System.in);
        String inputString = sc.nextLine().toString();
        String stringArray[] = inputString.split(" ");
        int num[] = new int[stringArray.length];
        for (int i = 0; i < stringArray.length; i++) {
            num[i] = Integer.parseInt(stringArray[i]);
        }
        int key = sc.nextInt();
        System.out.println(findFirstEqualLarger(num, key));
    }

    public static int findFirstEqualLarger(int[] array, int key) {
        int left = 0;
        int right = array.length - 1;
        while (left <= right) {
            int mid = (left + right) / 2;
            if (array[mid] >= key) {
                right = mid - 1;
            } else {
                left = mid + 1;
            }
        }
        return left;
    }
}