LeetCode 442 Find All Duplicates in an Array

LeetCode 442 Find All Duplicates in an Array

思路

本题将当前元素的value作为下一个元素的index，类似的还有 287 Find the Duplicate Number 和448 Find All Numbers Disappeared in an Array。

代码

class Solution {
public:
    vector<int> findDuplicates(vector<int>& nums) {
        vector<int> rs;
        int index;
        
        for (int i = 0; i < nums.size(); ++i) {
            index = abs(nums[i]) - 1;
            if (nums[index] < 0) rs.push_back(index + 1);
            else nums[index] = -nums[index];
        }
        
        return rs;
    }
};