Complete Competitive_Coding-3

Problem42.java

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+// Time Complexity : O(n)
+// Space Complexity : O(n)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+
+// Your code here along with comments explaining your approach
+
+class Solution {
+    public int findPairs(int[] nums, int k) {
+        Map<Integer, Integer> map = new HashMap<Integer, Integer>();
+        int n = nums.length;
+        int count = 0;
+
+        for (int i = 0; i < n; i++) {
+            map.put(nums[i], map.getOrDefault(nums[i],0)+1);
+        }
+
+        for (int num : map.keySet()) {
+            if (k > 0) {
+                if (map.containsKey(num - k)) {
+                    count++;
+                }
+            } else if (k == 0) {
+                if (map.get(num) > 1) {
+                    count++;
+                }
+            }
+        }
+
+        return count;
+    }
+}

Problem43.java

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+// Time Complexity : O(n^2)
+// Space Complexity : O(1)
+// Did this code successfully run on Leetcode : Yes
+// Any problem you faced while coding this : No
+
+
+// Your code here along with comments explaining your approach
+class Solution {
+    public List<List<Integer>> generate(int numRows) {
+
+        List<List<Integer>> result = new ArrayList<>();
+        result.add(Arrays.asList(1));
+
+        for(int i = 1; i < numRows; i++) {
+            List<Integer> prevRow = result.get(i - 1);
+            List<Integer> curRow = new ArrayList<>();
+            curRow.add(1);
+            for(int j = 1; j < prevRow.size(); j++) {
+                curRow.add(prevRow.get(j - 1) + prevRow.get(j));
+            }
+            curRow.add(1);
+            result.add(curRow);
+        }
+
+        return result;
+    }
+}