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.
思路：
用一个map，记录关键字和下标。
bool containsNearbyDuplicate(vector<int>& nums, int k) { if(nums.size()<=1 || k<=0) return false; map<int,int>m; for(int i=0;i<nums.size();i++) { if(m.count(nums[i]) && abs(m[nums[i]]-i)<=k) { return true; } else { m[nums[i]] = i; } } return false; }
[leetcode-219-Contains Duplicate II]
原文：http://www.cnblogs.com/hellowooorld/p/6940449.html