Welcome to channel "Leetcode Java".
In this channel I just want to provide my solutions of Leetcode problems in Java programming language.

#N1 Two sum
problem link =>https://leetcode.com/problems/two-sum/

class Solution {
public:
    vector<int> twoSum(vector<int>& nums, int target) {
        int a = 0, b = 0;
        for (int i = 0; i < nums.size() - 1; i ++) {
            for (int j = i + 1; j < nums.size(); j ++) {
                if ( nums[i] + nums[j] == target) {
                    a = i;
                    b = j;
                }
            }
        }
        return {a, b};
    }
};

#N26 Remove Duplicates from Sorted Array
problem link=>https://leetcode.com/problems/remove-duplicates-from-sorted-array/

class Solution {
    public int removeDuplicates(int[] nums) {
        int i = 0;
        for (int n : nums)
            if (i == 0 || n > nums[i-1])
            nums[i++] = n;
        return i;
    }
}

#N1431 Kids With the Greatest Number of Candies
problem link=>https://leetcode.com/problems/kids-with-the-greatest-number-of-candies/

class Solution {
    public List<Boolean> kidsWithCandies(int[] candies, int extra) {
        ArrayList<Boolean> ans = new ArrayList<Boolean>();
        int max=0;
        for(int candy: candies){
            max=Math.max(candy, max);
        }
        for(int candy: candies){
            ans.add(candy+extra>=max);
        }
        
        return ans;
    }
}

#N1920 Build Array from Permutation
problem link=>https://leetcode.com/problems/build-array-from-permutation/

class Solution {
    public int[] buildArray(int[] nums) {
        int[] ans=new int[nums.length];
        for(int i=0; i<nums.length; i++){
            ans[i]=nums[nums[i]];
        }
        return ans;
    }
}

#N1929 Concatenation of Array
problem link=>https://leetcode.com/problems/concatenation-of-array/

class Solution {
    public int[] getConcatenation(int[] nums) {
        int[] ans=new int[nums.length * 2];
        for(int i=0; i<nums.length; i++){
            ans[i]=nums[i];
            ans[i+nums.length]=nums[i];
        }
        return ans;
    }
}

#N1313 Decompress Run-Length Encoded List
problem link=>https://leetcode.com/problems/decompress-run-length-encoded-list/

#solution

class Solution {
    public int[] decompressRLElist(int[] nums) {
        int size=0;
        for(int i=0; i<nums.length; i+=2){
            size+=nums[i];
        }
        int[] ans=new int[size];
        for(int i=0, ix=0; i<nums.length; i+=2){
            for(int j=0; j<nums[i]; j++){
                ans[ix++]=nums[i+1];
            }
        }
        return ans;
    }
}

#N1773 Count Items Matching a Rule
problem link=>https://leetcode.com/problems/count-items-matching-a-rule/

#solution

class Solution {
    public int countMatches(List<List<String>> items, String ruleKey, String ruleValue) {
        int key, count=0;
        if(ruleKey.equals("type"))
            key=0;
        else if(ruleKey.equals("color"))
            key=1;
        else
            key=2;
        
        for(int i=0; i<items.size(); i++){
            if(items.get(i).get(key).equals(ruleValue))
                count++;
        }
        
        return count;
    }
}