Merge pull request #2571 from xCk27x/master

新增 0063.不同路径II 的TypeScript作法2

problems/0063.不同路径II.md

@@ -550,6 +550,27 @@ function uniquePathsWithObstacles(obstacleGrid: number[][]): number {
 };
 ```
 
+// 版本二: dp改為使用一維陣列，從終點開始遍歷
+```typescript
+function uniquePathsWithObstacles(obstacleGrid: number[][]): number {
+  const m = obstacleGrid.length;
+  const n = obstacleGrid[0].length;
+  
+  const dp: number[] = new Array(n).fill(0);
+  dp[n - 1] = 1;
+
+  // 由下而上，右而左進行遍歷
+  for (let i = m - 1; i >= 0; i--) {
+    for (let j = n - 1; j >= 0; j--) {
+      if (obstacleGrid[i][j] === 1) dp[j] = 0;
+      else dp[j] = dp[j] + (dp[j + 1] || 0); 
+    }
+  }
+
+  return dp[0];
+};
+```
+
 ### Rust
 
 ```Rust