very easy||o(n)
Intuition\n Describe your first thoughts on how to solve this problem. \n\n# Approach\n Describe your approach to solving the problem. \n\n# Complexity\n- Time 
# Intuition\n<!-- Describe your first thoughts on how to solve this problem. -->\n\n# Approach\n<!-- Describe your approach to solving the problem. -->\n\n# Complexity\n- Time complexity:\n<!-- Add your time complexity here, e.g. $$O(n)$$ -->\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```\nclass Solution {\npublic:\n    int countPairs(vector<int>& nums, int target) {\n        sort(nums.begin(),nums.end());\n        int i = 0,n = nums.size();\n        int j = n-1, ans = 0 ;\n        while(i<j){\n            int sum = nums[i]+nums[j];\n            if(sum>=target){\n                j--;\n            }else{\n                cout<<i<<" "<<j<<endl;\n                ans += abs(i-j);\n                i++;\n            }        \n            \n        }\n        return ans;\n    }\n};\n```
['C++']