g1001_1100.s1036_escape_a_large_maze.Solution Maven / Gradle / Ivy
Go to download
Show more of this group Show more artifacts with this name
Show all versions of leetcode-in-java11 Show documentation
Show all versions of leetcode-in-java11 Show documentation
Java Solution for LeetCode algorithm problems, continually updating
The newest version!
package g1001_1100.s1036_escape_a_large_maze;
// #Hard #Array #Hash_Table #Depth_First_Search #Breadth_First_Search
// #2022_02_27_Time_115_ms_(73.46%)_Space_79.4_MB_(60.66%)
import java.util.HashSet;
import java.util.Set;
public class Solution {
public boolean isEscapePossible(int[][] blocked, int[] source, int[] target) {
if (blocked.length == 0) {
return true;
}
Set blocks = new HashSet<>();
for (int[] b : blocked) {
if (target[0] * 1000000 + target[1] != b[0] * 1000000 + b[1]) {
blocks.add(b[0] * 1000000 + b[1]);
}
}
return dfs(blocks, source, source[0], source[1], new HashSet<>(), target)
&& dfs(blocks, target, target[0], target[1], new HashSet<>(), source);
}
private boolean dfs(
Set blocks, int[] start, int i, int j, Set visited, int[] target) {
if (i < 0
|| j < 0
|| i > 999999
|| j > 999999
|| blocks.contains(i * 1000000 + j)
|| visited.contains(i * 1000000 + j)) {
return false;
}
if (i == target[0] && j == target[1]) {
return true;
}
visited.add(i * 1000000 + j);
if (visited.size() > blocks.size() * (blocks.size() + 1)) {
return true;
}
return dfs(blocks, start, i + 1, j, visited, target)
|| dfs(blocks, start, i - 1, j, visited, target)
|| dfs(blocks, start, i, j + 1, visited, target)
|| dfs(blocks, start, i, j - 1, visited, target);
}
}