Refactor UniquePaths62: move to proper package structure

src/main/java/com/leetcode/medium/UniquePaths62.java

@@ -0,0 +1,45 @@
+// Tags: Dynamic Programming, DFS
+package com.leetcode.medium;
+
+import java.util.HashMap;
+import java.util.Map;
+
+public class UniquePaths62 {
+    private int uniquePathsMemoizationRecursive(int m, int n, Map<String, Integer> memo) {
+        if (m == 1 || n == 1) {
+            return 1;
+        }
+        String key = m + "," + n;
+        if (memo.containsKey(key)) {
+            return memo.get(key);
+        }
+        memo.put(key, this.uniquePathsMemoizationRecursive(m - 1, n, memo) + this.uniquePathsMemoizationRecursive(m, n - 1, memo));
+        return memo.get(key);
+    }
+
+    /**
+     * Time complexity: O(m*n)
+     * <p>
+     * Space complexity: O(m+n)
+     */
+    public int uniquePathsMemoization(int m, int n) {
+        return this.uniquePathsMemoizationRecursive(m, n, new HashMap<>());
+    }
+
+    /**
+     * Time complexity: O(m*n)
+     * <p>
+     * Space complexity: O(m*n)
+     */
+    public int uniquePathsTabulation(int m, int n) {
+        int[][] dp = new int[m + 1][n + 1];
+        dp[1][1] = 1;
+        for (int i = 0; i <= m; i++) {
+            for (int j = 0; j <= n; j++) {
+                if (i + 1 <= m) dp[i + 1][j] += dp[i][j];
+                if (j + 1 <= n) dp[i][j + 1] += dp[i][j];
+            }
+        }
+        return dp[m][n];
+    }
+}

src/test/java/com/leetcode/medium/UniquePaths62Test.java

@@ -0,0 +1,84 @@
+package com.leetcode.medium;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import java.time.Duration;
+
+import static org.junit.jupiter.api.Assertions.assertEquals;
+import static org.junit.jupiter.api.Assertions.assertTimeoutPreemptively;
+
+public class UniquePaths62Test {
+    private UniquePaths62 solution;
+
+    @BeforeEach
+    void setUp() {
+        solution = new UniquePaths62();
+    }
+
+    @Test
+    void testUniquePathsMemoization_Example1() {
+        int m = 3;
+        int n = 7;
+        int expected = 28;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsMemoization(m, n));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePathsMemoization_Example2() {
+        int m = 3;
+        int n = 2;
+        int expected = 3;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsMemoization(m, n));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePathsMemoization_Example3() {
+        int m = 23;
+        int n = 12;
+        int expected = 193536720;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsMemoization(m, n));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePathsTabulation_Example1() {
+        int m = 3;
+        int n = 7;
+        int expected = 28;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsTabulation(m, n));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePathsTabulation_Example2() {
+        int m = 3;
+        int n = 2;
+        int expected = 3;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsTabulation(m, n));
+
+        assertEquals(expected, result);
+    }
+
+    @Test
+    void testUniquePathsTabulation_Example3() {
+        int m = 23;
+        int n = 12;
+        int expected = 193536720;
+
+        int result = assertTimeoutPreemptively(Duration.ofMillis(100), () -> solution.uniquePathsTabulation(m, n));
+
+        assertEquals(expected, result);
+    }
+}