From 32dada4f6d071c10643dd69c356aeba74601cf21 Mon Sep 17 00:00:00 2001
From: Qiyu Liang <61932152+Guicai996@users.noreply.github.com>
Date: Mon, 28 Feb 2022 15:01:23 +0800
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0063.不同路径II，L159-190 增加空间优化版本c++代码
---
 problems/0063.不同路径II.md | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

diff --git a/problems/0063.不同路径II.md b/problems/0063.不同路径II.md
index 8e82007e..86c42150 100644
--- a/problems/0063.不同路径II.md
+++ b/problems/0063.不同路径II.md
@@ -155,6 +155,39 @@ public:
 * 时间复杂度：$O(n × m)$，n、m 分别为obstacleGrid 长度和宽度
 * 空间复杂度：$O(n × m)$
 
+
+同样我们给出空间优化版本：
+```CPP
+class Solution {
+public:
+    int uniquePathsWithObstacles(vector<vector<int>>& obstacleGrid) {
+        if (obstacleGrid[0][0] == 1)
+            return 0;
+        vector<int> dp(obstacleGrid[0].size());
+        for (int j = 0; j < dp.size(); ++j)
+            if (obstacleGrid[0][j] == 1)
+                dp[j] = 0;
+            else if (j == 0)
+                dp[j] = 1;
+            else
+                dp[j] = dp[j-1];
+
+        for (int i = 1; i < obstacleGrid.size(); ++i)
+            for (int j = 0; j < dp.size(); ++j){
+                if (obstacleGrid[i][j] == 1)
+                    dp[j] = 0;
+                else if (j != 0)
+                    dp[j] = dp[j] + dp[j-1];
+            }
+        return dp.back();
+    }
+};
+```
+
+* 时间复杂度：$O(n × m)$，n、m 分别为obstacleGrid 长度和宽度
+* 空间复杂度：$O(m)$
+
+
 ## 总结
 
 本题是[62.不同路径](https://programmercarl.com/0062.不同路径.html)的障碍版，整体思路大体一致。