Given an integer array nums and an integer val, remove all occurrences of val in nums in-place. The order of the elements may be changed. Then return the number of elements in nums which are not equal to val.
Consider the number of elements in nums which are not equal to val be k, to get accepted, you need to do the following things:
- Change the arrayÂ
nums such that the firstÂk elements ofÂnums contain the elements which are not equal toÂval. The remaining elements ofÂnums are not important as well as the size ofÂnums. - ReturnÂ
k.
Custom Judge:
The judge will test your solution with the following code:
int[] nums = [...]; // Input array
int val = ...; // Value to remove
int[] expectedNums = [...]; // The expected answer with correct length.
// It is sorted with no values equaling val.
int k = removeElement(nums, val); // Calls your implementation
assert k == expectedNums.length;
sort(nums, 0, k); // Sort the first k elements of nums
for (int i = 0; i < actualLength; i++) {
assert nums[i] == expectedNums[i];
}Example 1:
Input: nums = [3,2,2,3], val = 3
Output: 2, nums = [2,2,_,_]
Explanation: Your function should return k = 2, with the first two elements of nums being 2.
It does not matter what you leave beyond the returned k (hence they are underscores).Example 2:
Input: nums = [0,1,2,2,3,0,4,2], val = 2
Output: 5, nums = [0,1,4,0,3,_,_,_]
Explanation: Your function should return k = 5, with the first five elements of nums containing 0, 0, 1, 3, and 4.
Note that the five elements can be returned in any order.
It does not matter what you leave beyond the returned k (hence they are underscores).Constraints:
0 <= nums.length <= 1000 <= nums[i] <= 500 <= val <= 100
Problem Link : Remove Element – LeetCode
Solution:
Approach:
- Use Two pointers method.
- After shifting the val to the right side of the array.
- Just return the value of k which is length of array excluding val.
Java Code:
public int removeElement(int[] nums, int val) {
int i = 0,j=0;
while(j < nums.length) {
if (nums[j] != val) {
nums[i] = nums[j];
i++;
}
j++;
}
return i;
}Complexity:
- Time complexity:O(n)
- Space complexity:O(1)
Hello, my name is Deependra Singh. I hold B.tech degree in Computer Science & Engineering from Institute of Engineering & Technology, Lucknow. Currently, I am working in Steel Authority of India Limited as a Software Developer.