Add unique paths solution

Author: hyunjung-choi

unique-paths/hyunjung-choi.kt

@@ -0,0 +1,18 @@
+/**
+ * 시간 복잡도: O(m * n)
+ * 공간 복잡도: O(n)
+ */
+
+class Solution {
+    fun uniquePaths(m: Int, n: Int): Int {
+        val dp = IntArray(n) { 1 }
+
+        for (i in 1 until m) {
+            for (j in 1 until n) {
+                dp[j] += dp[j - 1]
+            }
+        }
+
+        return dp[n - 1]
+    }
+}