leetcode 220. 存在重复元素 III

https://leetcode-cn.com/problems/contains-duplicate-iii/

方法1

class Solution {
public:
    bool containsNearbyAlmostDuplicate(vector& nums, int k, int t) {
        if (t<0 || k ==0) return false;
        
        set _set;
        for (int i = 0; i < nums.size(); ++i)
        {
            auto it = _set.lower_bound((long)nums[i]-t);
            if (it != _set.end() && *it <= (long)nums[i]+t) return true;
            
            _set.insert(nums[i]);
            if (i >= k) _set.erase(nums[i-k]);
        }
        return false;
    }
};

方法2 桶

class Solution {
public:
    bool containsNearbyAlmostDuplicate(vector& nums, int k, int t) {
        if (t<0 || k ==0) return false;
        
        unordered_map d;
        long w = (long)t + 1;
        for (int i = 0; i < nums.size(); ++i)
        {
            long id = getID(nums[i],w);
            if (d.count(id)) return true;
            if (d.count(id-1) && nums[i] - d[id-1] < w) return true;
            if (d.count(id+1) && d[id+1] - nums[i] < w) return true;
           
            d[id] = nums[i];
            if (i >= k) d.erase(getID(nums[i-k],w));           
        }
        return false;
    }
    
    long getID(long x, long w)
    {
        return x<0?((x+1)/w-1):x/w;
    }
};