@@ -66,7 +66,7 @@ dp[i][j] :表示从(0 ,0)出发,到(i, j) 有dp[i][j]条不同的路
6666
6767所以代码为:
6868
69- ```
69+ ``` cpp
7070if (obstacleGrid[i][j] == 0 ) { // 当(i, j)没有障碍的时候,再推导dp[ i] [ j ]
7171 dp[ i] [ j ] = dp[ i - 1] [ j ] + dp[ i] [ j - 1 ] ;
7272}
@@ -76,7 +76,7 @@ if (obstacleGrid[i][j] == 0) { // 当(i, j)没有障碍的时候,再推导dp[i
7676
7777在[ 62.不同路径] ( https://programmercarl.com/0062.不同路径.html ) 不同路径中我们给出如下的初始化:
7878
79- ```
79+ ``` cpp
8080vector<vector<int >> dp (m, vector<int >(n, 0)); // 初始值为0
8181for (int i = 0; i < m; i++) dp[ i] [ 0 ] = 1;
8282for (int j = 0; j < n; j++) dp[ 0] [ j ] = 1;
@@ -138,6 +138,8 @@ public:
138138 int uniquePathsWithObstacles(vector<vector<int >>& obstacleGrid) {
139139 int m = obstacleGrid.size();
140140 int n = obstacleGrid[ 0] .size();
141+ if (obstacleGrid[ m - 1] [ n - 1 ] == 1 || obstacleGrid[ 0] [ 0 ] == 1) //如果在起点或终点出现了障碍,直接返回0
142+ return 0;
141143 vector<vector<int >> dp(m, vector<int >(n, 0));
142144 for (int i = 0; i < m && obstacleGrid[ i] [ 0 ] == 0; i++) dp[ i] [ 0 ] = 1;
143145 for (int j = 0; j < n && obstacleGrid[ 0] [ j ] == 0; j++) dp[ 0] [ j ] = 1;
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