Easiest two pointer approach
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. $$O(n)$$ -->O(n^2)\n\n- Space complexity:\n<!-- Add your space complexity here, e.g. $$O(n)$$ -->\n\n# Code\n```java []\nclass Solution {\n    public int countPairs(List<Integer> nums, int target) { \n        int n=nums.size();\n        int count=0;\n        for(int i=0;i<n;i++){\n            int j=i+1; // because i<j always\n            while(j<n){\n                if((nums.get(i)+nums.get(j)<target)){\n                    count++;\n                }\n                j++;\n            }\n        } \n        return count;\n    }\n}\n```
['Java']