-
Notifications
You must be signed in to change notification settings - Fork 1
Expand file tree
/
Copy pathUniquePaths2.java
More file actions
72 lines (57 loc) · 2.46 KB
/
Copy pathUniquePaths2.java
File metadata and controls
72 lines (57 loc) · 2.46 KB
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
// A robot is located at the top-left corner of a m x n grid
// (marked 'Start' in the diagram below).
// The robot can only move either down or right at any point in time.
// The robot is trying to reach the bottom-right corner of the grid
// (marked 'Finish' in the diagram below).
// Now consider if some obstacles are added to the grids. How many unique paths would there be?
// See: https://leetcode.com/problems/unique-paths-ii/
package leetcode.dynamic_programming;
public class UniquePaths2 {
public int uniquePathsWithObstacles(int[][] obstacleGrid) {
int n = obstacleGrid.length;
int m = obstacleGrid[0].length;
int[][] dp = new int[n][m];
for (int i = 0; i < n; i++) {
if (obstacleGrid[i][0] != 1)
dp[i][0] = 1;
else
break;
}
for (int i = 0; i < m; i++) {
if (obstacleGrid[0][i] != 1)
dp[0][i] = 1;
else
break;
}
for (int i = 1; i < n; i++) {
for (int j = 1; j < m; j++) {
if (obstacleGrid[i][j] != 1)
if (obstacleGrid[i - 1][j] == 1 && obstacleGrid[i][j - 1] != 1) {
dp[i][j] = dp[i][j - 1];
} else if (obstacleGrid[i - 1][j] != 1 && obstacleGrid[i][j - 1] == 1) {
dp[i][j] = dp[i - 1][j];
} else if(obstacleGrid[i - 1][j] != 1 && obstacleGrid[i][j - 1] != 1) {
dp[i][j] = dp[i - 1][j] + dp[i][j - 1];
}
}
}
return dp[n - 1][m - 1];
}
public static void main(String[] args) {
UniquePaths2 sln =new UniquePaths2();
int[][] g1 = new int[3][7];
g1[1][2] = 1;
System.out.println(sln.uniquePathsWithObstacles(g1)); // 13
g1[1][3] = 1;
System.out.println(sln.uniquePathsWithObstacles(g1)); // 9
int[][] g2 = new int[3][3];
g2[1][1] = 1;
System.out.println(sln.uniquePathsWithObstacles(g2)); // 2
int[][] g3 = new int[][] {{1}};
System.out.println(sln.uniquePathsWithObstacles(g3)); // 0
int[][] g4 = new int[][] {{1, 0}};
System.out.println(sln.uniquePathsWithObstacles(g4)); // 0
int[][] g5 = new int[][] {{0, 1, 0}};
System.out.println(sln.uniquePathsWithObstacles(g5)); // 0
}
}