九度 1516 调整数组顺序使奇数位于偶数前面

Posted 2020-07-08 qingyezhu

import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.StreamTokenizer;

public class Main{

    /**
     * @param args
     * @throws IOException
     */
    public static void main(String[] args) throws IOException {
        //System.setIn(new FileInputStream("data.in"));
        StreamTokenizer in = new StreamTokenizer(new BufferedReader(
                new InputStreamReader(System.in)));
        while (in.nextToken() != StreamTokenizer.TT_EOF) {
            int n = (int) in.nval;
            int evenIndex = 0, oddIndex = 0;
            int[] evenArr = new int[n];
            int[] oddArr = new int[n];
            for (int i = 0; i < n; i++) {
                in.nextToken();
                int m = (int) in.nval;
                if ((m & 1) == 0) {
                    evenArr[evenIndex++] = m;
                } else {
                    oddArr[oddIndex++] = m;
                }
            }
            for (int i = 0; i < oddIndex; i++) {
                if (i > 0) {
                    System.out.print(" ");
                }
                System.out.print(oddArr[i]);
            }
            if (oddIndex > 0) {
                System.out.print(" ");
            }
            for (int i = 0; i < evenIndex; i++) {
                if (i > 0) {
                    System.out.print(" ");
                }
                System.out.print(evenArr[i]);
            }
            System.out.println();

        }
    }
}

扩展：当不需要关注奇偶数原来的顺序时

package com.wangzhu.algorithm;

import java.util.Arrays;
import java.util.Scanner;

public class ArrayOddEvenMove {

    public static void main(String[] args) {
        Scanner cin = new Scanner(System.in);
        while(cin.hasNext()){
            int n = cin.nextInt();
            int[] arr = new int[n];
            while(cin.hasNext()){
                for(int i = 0;i < n;i ++){
                    arr[i] = cin.nextInt();
                }
                execute1(arr);
                System.out.println(Arrays.toString(arr));
            }
        }
    }
    
    public static void execute1(int[] arr){
        //记录奇数的当前位置
        int start = -1;
        for(int i = 0, len = arr.length;i < len;i ++){
            if(!isEven(arr[i])){
                //当找到一个奇数，则将当前的位置的数交换到连续奇数后面
                start ++;
                swap(i, start, arr);
            }
        }
    }
    
    public static void execute(int[] arr){
        int left = 0, right = arr.length - 1;
        while(left < right){
            while(left < right && !isEven(arr[left])){
                left ++;
            }
            
            while(left < right && isEven(arr[right])){
                --right;
            }
            
            if(left <right){
                swap(left, right, arr);
            }
        }
    }

    private static boolean isEven(int num) {
        return (num & 1) == 0;
    }
    
    private static void swap(int i, int j, int[] arr){
        int tmp = arr[i];
        arr[i] = arr[j];
        arr[j] = tmp;
    }
}

 

参考：

http://www.cnblogs.com/xing901022/p/3755795.html

http://blog.chinaunix.net/uid-26548237-id-3753247.html

http://www.cnblogs.com/kaituorensheng/p/3607118.html