26 remove duplicates from sorted array

Given a sorted array, remove the duplicates in place such that each element appear only once and return the new length.

Do not allocate extra space for another array, you must do this in place with constant memory.

For example, Given input array nums = [1,1,2],

Your function should return length = 2, with the first two elements of nums being 1 and 2 respectively. It doesn't matter what you leave beyond the new length.

1

使用一个新指针idx,指向当前有效的数组，使用一个遍历指针i,利用数组已经有序的条件，将nums[i]与nums[idx]比较， 相同则继续遍历，不相同则更新idx指针，同时将nums[i]保存到nums[idx]。

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public int removeDuplicates(int[] nums) {
           if(nums == null || nums.length == 0) return 0;
           int n = nums.length;
           int idx = 0;
           for(int i = 1; i < n; i++){
                if(nums[i] != nums[idx]){
                    nums[++idx] = nums[i];
                }
           }
           return idx+1;
    }

2 most votes

方法类似。