Contains Duplicate III

typedef long long ll;
class Solution {
public:
    bool containsNearbyAlmostDuplicate(vector<int>& nums, int k, int t) {
        int n = nums.size();
        if(n == 0 || k <= 0)
            return false;
        vector<pair<int,int>> num_index;
        for(int i=0;i<n;i++) {
            num_index.push_back(make_pair(nums[i],i));
        }
        sort(num_index.begin(),num_index.end());
        int curr=0;
        int next=1;
        while(next<n)
        {
            ll a = num_index[curr].first;
            ll b = num_index[next].first;
            if(abs(num_index[curr].second-num_index[next].second) <= k && abs(a-b)<=t)
                return true;
            if(abs(num_index[curr].second-num_index[next].second)>k)
                next++;
            if(abs(a-b)>t)
                curr++;
            if(curr==next)
                next++;
        }
        return false;

    }
};