[LeetCode] Contains Duplicate II

Contains Duplicate II

 Given an array of integers and an integer k, return true if and only if there are two distinct indices i and j in the array such that nums[i] = nums[j] and the difference between i and j is at most k.

解题思路：

可以用一个set记录滑动窗口大小的所有元素，随着滑动窗口往右移，左边的陆续删除，添加右边的。若set中出现相同元素，那么返回true。否则返回false。注意题意中的k是指j-i=k。

class Solution {
public:
    bool containsNearbyDuplicate(vector<int>& nums, int k) {
        int len = nums.size();
        if(k <= 0 || len<=0){
            return false;
        }
        set<int> s;
        for(int i = 0; i<len; i++){
            if(s.size()>k){
                s.erase(nums[i - k - 1]);
            }
            if(s.find(nums[i])!=s.end()){
                return true;
            }
            s.insert(nums[i]);
        }
        return false;
    }
};

[LeetCode] Contains Duplicate II

原文：http://blog.csdn.net/kangrydotnet/article/details/46277331