LeetCode442. 数组中重复的数据（原地哈希）

442. 数组中重复的数据

原地哈希

class Solution {
     
public:
    //原地哈希：将vector当做哈希表自行原地哈希
    vector<int> findDuplicates(vector<int>& nums) {
     
        int len = nums.size();
        if(len <= 1) return vector<int>();
        vector<int> ans;
        for(int i = 0; i < len; i++) {
     
            while(nums[nums[i] - 1] != nums[i]) {
     
                swap(nums, nums[i] - 1, i);
            }
        }
        for(int i = 0; i < len; i++) {
     
            if(nums[i] == i + 1) {
     
                continue;
            }else {
     
                ans.push_back(nums[i]);
            }
        }
        sort(ans.begin(), ans.end());
        return ans;
    }
private:
    void swap(vector<int>& nums, int i, int j) {
     
        int tmp = nums[i];
        nums[i] = nums[j];
        nums[j] = tmp;
    }
};