Merge pull request neetcode-gh#3349 from drxlx/0063-unique-paths-ii

Ykhan799 · web-flow · commit 57dff985e06e · 2024-09-20T23:13:56.000-07:00
Create 0063-unique-paths-ii.swift
diff --git a/swift/0063-unique-paths-ii.swift b/swift/0063-unique-paths-ii.swift
@@ -0,0 +1,23 @@
+/**
+ * Question Link: https://leetcode.com/problems/unique-paths-ii/
+ */
+
+ class Solution {
+    func uniquePathsWithObstacles(_ obstacleGrid: [[Int]]) -> Int {
+        let rows = obstacleGrid.count
+        let cols = obstacleGrid[0].count
+        var dp = [Int](repeating: 0, count: cols)
+        dp[cols - 1] = 1
+
+        for r in stride(from: rows - 1, to: -1, by: -1) {
+            for c in stride(from: cols - 1, to: -1, by: -1) {
+                if obstacleGrid[r][c] == 1 {
+                    dp[c] = 0
+                } else if c + 1 < cols {
+                    dp[c] = dp[c] + dp[c + 1]
+                }
+            }
+        }
+        return dp[0]
+    }
+}
