算法

/** 首尾互换* {1,2,3,4,5}*/int[] arr = {1,2,3,4,5,6,7,8,9};int tmp;for (int i=0,j=arr.length-1; i<j; i++,j--) {tmp = arr[i];arr[i] = arr[j];arr[j] = tmp;}System.out.println(Arrays.toString(arr));

/** 排序* int a=3, b=2, c=1* 按照从小到大排序后的顺序为：1 2 3 */int a=3, b=2, c=1;if(a>b){int temp = a;a = b;b = temp;}if(a>c){int temp = a;a = c;c = temp;}if(b>c){int temp = b;b = c;c = temp;}System.out.println(a+" "+b+" "+c);

/** 奇数放左边，偶数放右边*/int[] arr = {1,2,3,4,5,6,7,8,9};int count = 0;int tmp;for (int i=0; i<arr.length; i++) {if (arr[i]%2!=0) {tmp = arr[count];arr[count] = arr[i];arr[i] = tmp;count++;}}System.out.println(Arrays.toString(arr));