Contains Duplicate III

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

class Solution {
public:
    bool containsNearbyAlmostDuplicate(vector<int>& nums, int k, int t) {
        multiset <long long> bst;
        for(int i=0;i<nums.size();i++)
        {
            if(bst.size()==k+1) bst.erase(bst.find(nums[i-k-1]));
            auto lb=bst.lower_bound(nums[i]);
            if(lb!=bst.end()&&abs(*lb-nums[i])<=t) return true;
            auto ub=bst.upper_bound(nums[i]);
            if(ub!=bst.begin()&&abs(*(--ub)-nums[i])<=t) return true;
            bst.insert(nums[i]);
        }
        return false;
    }
};

lower_bound 返回大于等于n的最小键值的序号。

upper_bound 返回小于n的最大键值的序号+1.

返回的位置均为可直接插入的位置。