问题:
Given an array nums
, write a function to move all 0
's to the end of it while maintaining the relative order of the non-zero elements.
For example, given nums = [0, 1, 0, 3, 12]
, after calling your function, nums
should be [1, 3, 12, 0, 0]
.
Note:
- You must do this in-place without making a copy of the array.
- Minimize the total number of operations.
分析:
双指针。 这一问题的一个中间步骤,应该是前m个数有序, 中间是n个0, 最后l个数无序。 第一个指针指向第一个0,第二个指针指向l个无序数中的第一个。
当后个指针指向最后一个数的后一个位置时,所有步骤结束。
class Solution { public void moveZeroes(int[] nums) { for(int i =0, j=0; j<=nums.length; j++) { if(nums[j] == 0) { continue; } else { nums[i] = nums[j]; i++; nums[j] = 0; } } } }
结果:
Run Code Status: Runtime Error Run Code Result: Your input [0,1,0,3,12] Your answer Exception in thread "main" java.lang.ArrayIndexOutOfBoundsException: 5 at Solution.moveZeroes(Solution.java:5) at __DriverSolution__.__helper__(__Driver__.java:8) at __Driver__.main(__Driver__.java:52)
分析:
二次:
class Solution { public void moveZeroes(int[] nums) { for(int i =0, j=0; j<nums.length; j++) { if(nums[j] == 0) { continue; } else { nums[i] = nums[j]; i++; nums[j] = 0; } } } }
结果:
Submission Result: Wrong Answer Input: [1] Output: [0] Expected: [1]
分析:
还是不能直接赋值0.
三次:
class Solution { public void moveZeroes(int[] nums) { int temp; for(int i =0, j=0; j<nums.length; j++) { if(nums[j] == 0) { continue; } else { temp = nums[i]; nums[i] = nums[j]; i++; nums[j] = temp; } } } }
结果:
总结:
注意边界条件。