[Aug 01] Added leetcode daily challenge problem

Author: SunilGudivada

Diff for: leetCode/DailyChallenge/_2022/FEB/_03FEB2022_4SumII.java

@@ -36,17 +36,17 @@
  * -2^28 <= nums1[i], nums2[i], nums3[i], nums4[i] <= 2^28
  */
 public class _03FEB2022_4SumII {
-    public int fourSumCount(int[] nums1, int[] nums2, int[] nums3, int[] nums4) {
-        var pairCountBySum = new HashMap<Integer, Integer>();
-        for (var num1 : nums1)
-            for (var num2 : nums2)
-                pairCountBySum.compute(num1 + num2, (k, sumCount) -> sumCount == null ? 1 : sumCount + 1);
-
-        var fourSumCount = 0;
-        for (var num3 : nums3)
-            for (var num4 : nums4)
-                fourSumCount += pairCountBySum.getOrDefault(-(num3 + num4), 0);
-
-        return fourSumCount;
-    }
+//    public int fourSumCount(int[] nums1, int[] nums2, int[] nums3, int[] nums4) {
+//        var pairCountBySum = new HashMap<Integer, Integer>();
+//        for (var num1 : nums1)
+//            for (var num2 : nums2)
+//                pairCountBySum.compute(num1 + num2, (k, sumCount) -> sumCount == null ? 1 : sumCount + 1);
+//
+//        var fourSumCount = 0;
+//        for (var num3 : nums3)
+//            for (var num4 : nums4)
+//                fourSumCount += pairCountBySum.getOrDefault(-(num3 + num4), 0);
+//
+//        return fourSumCount;
+//    }
 }

Diff for: leetCode/problems/_62_uniquePaths_1.java

@@ -0,0 +1,50 @@
+package leetCode.problems;
+
+public class _62_uniquePaths_1 {
+
+    public int solution_recursive(int m, int n) {
+        return helper_recursive(m, n, 0, 0);
+    }
+
+    public int helper_recursive(int m, int n, int x, int y) {
+        if (x == m - 1 || y == n - 1) return 1;
+        if (x >= m || y >= n) return 0;
+
+        return helper_recursive(m, n, x + 1, y) + helper_recursive(m, n, x, y + 1);
+    }
+
+    public int solution_dp(int m, int n) {
+        int[][] dp = new int[m][n];
+
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                if (i == 0 || j == 0) {
+                    dp[i][j] = 1;
+                } else {
+                    dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
+                }
+            }
+        }
+
+        return dp[m - 1][n - 1];
+    }
+
+    public int solution_nCr(int m, int n) {
+        int N = m + n - 2;
+        int r = Math.min(m, n) - 1;
+        double ans = 1;
+
+        for (int i = 1; i <= r; i++) {
+            ans = ans * (N - r + i) / i;
+        }
+
+        return (int) ans;
+
+    }
+
+    public static void main(String[] args) {
+
+        _62_uniquePaths_1 obj = new _62_uniquePaths_1();
+        System.out.println(obj.solution_recursive(3, 2));
+    }
+}