solves unique paths

Author: anishLearnsToCode

Diff for: README.md

@@ -59,6 +59,7 @@
 |  58  | [Length of Last Word](https://leetcode.com/problems/length-of-last-word)                                                                                  |                                 [![Java](assets/java.png)](src/LengthOfLastWord.java) [![Python](assets/python.png)](python/length_of_last_word.py)                                  |                                                                                                                                   |
 |  59  | [Spiral Matrix II](https://leetcode.com/problems/spiral-matrix-ii)                                                                                        |                                                                 [![Java](assets/java.png)](src/SpiralMatrixII.java)                                                                  |                                                                                                                                   |
 |  61  | [Rotate List](https://leetcode.com/problems/rotate-list)                                                                                                  |                                                                   [![Java](assets/java.png)](src/RotateList.java)                                                                    |                                                                                                                                   |
+|  62  | [Unique Paths](https://leetcode.com/problems/unique-paths)                                                                                                |                                                                   [![Java](assets/java.png)](src/UniquePaths.java)                                                                   |                                                                                                                                   |
 |  66  | [Plus One](https://leetcode.com/problems/plus-one)                                                                                                        |                                           [![Java](assets/java.png)](src/PlusOne.java) [![Python](assets/python.png)](python/plus_one.py)                                            |                                                                                                                                   |
 |  67  | [Add Binary](https://leetcode.com/problems/add-binary)                                                                                                    |                                         [![Java](assets/java.png)](src/AddBinary.java) [![Python](assets/python.png)](python/add_binary.py)                                          |                                                                                                                                   |
 |  69  | [Sqrt(x)](https://leetcode.com/problems/sqrtx)                                                                                                            |                                              [![Java](assets/java.png)](src/Sqrtx.java) [![Python](assets/python.png)](python/sqrt.py)                                               |                                                                                                                                   |

Diff for: src/UniquePaths.java

@@ -0,0 +1,15 @@
+// https://leetcode.com/problems/unique-paths
+// T: O(min(m, n))
+// S: O(1)
+
+public class UniquePaths {
+    public int uniquePaths(int m, int n) {
+        final int M = Math.max(m, n) - 1, N = Math.min(m, n) - 1;
+        long result = 1;
+        for (int i = M + 1, j = 1 ; i <= M + N ; i++, j++) {
+            result *= i;
+            result /= j;
+        }
+        return (int) result;
+    }
+}