com.github.sinjar.common.util.common.ArrUtils Maven / Gradle / Ivy

Go to download
package com.github.sinjar.common.util.common;

import java.util.Arrays;

/**
 * Description : 
 *
 * @author CPF
 * Date: 2020/3/27 14:42
 */
public class ArrUtils {

    private ArrUtils(){}

    /**
     * 获取一维数组中相邻 number 个数的最大乘积
     *
     * @param arr 待处理的数组
     * @param number 相邻数量
     * @return
     * throw new RuntimeException (arr.length < number)
     */
    public static int getMaxProductInArr(int[] arr, int number) throws Throwable {
        int len = arr.length;
        if (len < number){
            throw new RuntimeException("arr太小!");
        }
        int[] num = Arrays.copyOf(arr, number);

        int product = Arrays.stream(num).reduce((a, b) -> a*b).orElseThrow(Throwable::new);
        int cur = 0;
        int tmpProdect;
        for (int i = number; i < len; i ++) {
            num[cur] = arr[i];
            tmpProdect = Arrays.stream(num).reduce((a, b) -> a*b).orElseThrow(Throwable::new);
            if (tmpProdect > product) {
                product = tmpProdect;
            }
            cur ++;
            cur = cur % number;
        }
        return product;
    }

    /**
     * 转置矩阵, 矩阵必须是方形矩阵
     * @param matrix 矩阵数组
     */
    public static void transposeMatrix(Object[][] matrix){
        if (matrix.length != matrix[0].length){
            throw new RuntimeException("matrix.length != matrix[0].length");
        }
        int length = matrix.length;
        Object tmp;
        for (int i = 0; i < length; i ++){
            for (int j = 0; j < i; j++){
                tmp = matrix[i][j];
                matrix[i][j] = matrix[j][i];
                matrix[j][i] = tmp;
            }
        }
    }

    /**
     * 转置矩阵
     *
     * @param matrix 矩阵数组
     */
    public static void transposeMatrix(int[][] matrix){
        if (matrix.length != matrix[0].length){
            throw new RuntimeException("matrix.length != matrix[0].length");
        }
        int length = matrix.length;
        int tmp;
        for (int i = 0; i < length; i ++){
            for (int j = 0; j < i; j++){
                tmp = matrix[i][j];
                matrix[i][j] = matrix[j][i];
                matrix[j][i] = tmp;
            }
        }
    }


    /**
     * 将一个字符串数组转换为int数组
     * @param strArr 待处理的字符串数组
     * @return 转换后的int数组
     */
    public static int[] transStrArrToIntArr(String[] strArr){
        int len = strArr.length;
        int[] intArr = new int[len];
        for (int i = 0; i < len; i++){
            intArr[i] = Integer.parseInt(strArr[i]);
        }
        return intArr;
    }


    /**
     * 全层数组深拷贝,
     * @param arr 拷贝后的数组
     */
    @SuppressWarnings("unchecked")
    public static  T[] fullClone(T[] arr){
        int len = arr.length;
        T[] copy = arr.clone();
        for (int i = 0; i 类型
     */
    public static  void fullFill(T[] arr, T val) {
        int len = arr.length;
        for (int i = 0; i end: %s 间隔不能为 : %s", start, end, interval));
        }
        if (len == 0) {
            int[] arr = new int[1];
            arr[0] = start;
            return arr;
        }
        int[] result = new int[len];
        for (int i = 0, n = start; i < len; i++, n += interval) {
            result[i] = n;
        }
        return result;
    }

}