week 7

Author: YeonguChoe

unique-paths/yeonguchoe.cpp

@@ -0,0 +1,14 @@
+class Solution {
+public:
+    int combination(int n, int r) {
+        int k = n - r > r ? r : n - r;
+        unsigned long long result = 1;
+        for (int i = 0; i < k; i++) {
+            result = result * (n - i) / (i + 1);
+        }
+        return result;
+    }
+    int uniquePaths(int m, int n) { return combination(m - 1 + n - 1, m - 1); }
+    // 시간 복잡도: O(min(m,n))
+    // 공간 복잡도: O(1)
+};