LeetCode——Contains Duplicate II

Question

Given an array of integers and an integer k, find out whether there are two distinct indices i and j in the array such that nums[i] = nums[j] and the absolute difference between i and j is at most k.

Solution

哈希表。

Code

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        map<int, int> table;
        for (int i = 0; i < nums.size(); i++) {
            if (table.find(nums[i]) == table.end())
                table[nums[i]] = i;
            else {
                int front = table[nums[i]];
                table[nums[i]] = i;
                if (i - front <= k)
                    return true;
                
            }
        }
        return false;
    }
};