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Merge pull request #1633 from zhicheng-lee/zhicheng-lee-patch-10

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更新 0063.不同路径II.md Java代码
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程序员Carl
2022-09-11 10:35:54 +08:00
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parent a758803df6 efaa04f8e2
commit cc5a2feda3
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problems/0063.不同路径II.md
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@ -210,24 +210,54 @@ public:
```java ```java
class Solution { class Solution {
public int uniquePathsWithObstacles(int[][] obstacleGrid) { public int uniquePathsWithObstacles(int[][] obstacleGrid) {
int n = obstacleGrid.length, m = obstacleGrid[0].length; int m = obstacleGrid.length;
int[][] dp = new int[n][m]; int n = obstacleGrid[0].length;
int[][] dp = new int[m][n];
for (int i = 0; i < m; i++) {
if (obstacleGrid[0][i] == 1) break; //一旦遇到障碍，后续都到不了 //如果在起点或终点出现了障碍，直接返回0
dp[0][i] = 1; if (obstacleGrid[m - 1][n - 1] == 1 || obstacleGrid[0][0] == 1) {
return 0;
} }
for (int i = 0; i < n; i++) {
if (obstacleGrid[i][0] == 1) break; ////一旦遇到障碍，后续都到不了 for (int i = 0; i < m && obstacleGrid[i][0] == 0; i++) {
dp[i][0] = 1; dp[i][0] = 1;
} }
for (int i = 1; i < n; i++) { for (int j = 0; j < n && obstacleGrid[0][j] == 0; j++) {
for (int j = 1; j < m; j++) { dp[0][j] = 1;
if (obstacleGrid[i][j] == 1) continue; }
dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
for (int i = 1; i < m; i++) {
for (int j = 1; j < n; j++) {
dp[i][j] = (obstacleGrid[i][j] == 0) ? dp[i - 1][j] + dp[i][j - 1] : 0;
} }
} }
return dp[n - 1][m - 1]; return dp[m - 1][n - 1];
}
}
```
```java
// 空间优化版本
class Solution {
public int uniquePathsWithObstacles(int[][] obstacleGrid) {
int m = obstacleGrid.length;
int n = obstacleGrid[0].length;
int[] dp = new int[n];
for (int j = 0; j < n && obstacleGrid[0][j] == 0; j++) {
dp[j] = 1;
}
for (int i = 1; i < m; i++) {
for (int j = 0; j < n; j++) {
if (obstacleGrid[i][j] == 1) {
dp[j] = 0;
} else if (j != 0) {
dp[j] += dp[j - 1];
}
}
}
return dp[n - 1];
} }
} }
``` ```