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| class Solution {
class Step {
public List<Step> walked = new LinkedList<Step>();
public int obstaclesCount = 0;
public Step from = null;
public final int row, column;
Step(int i, int j) {
this.row = i;
this.column = j;
walked.add(this);
}
Step(int i, int j, List<Step> walked, Step from) {
this(i, j);
this.from = from;
this.walked.addAll(walked);
}
public boolean canWalking(int x) {
switch (x) {
case 1:
return true;
case 2:
return true;
case 0:
return true;
}
return false;
}
public int walking(int[][] grid) {
int count = 0;
if (grid[row][column] == -1) {
System.out.println("-1");
return 0;
}
if (grid[row][column] == 2) {
if (this.walked.size() + obstaclesCount == grid[0].length * grid.length)
return 1;
return 0;
}
if (grid[row][column] == 0 || grid[row][column] == 1) {
if (row > 0) {
if (canWalking(grid[row - 1][column])) {
Step top = new Step(row - 1, column, walked, this);
if (!walked.contains(top)) {
top.obstaclesCount = this.obstaclesCount;
count += top.walking(grid);
}
}
}
if ((row + 1) < grid.length) {
if (canWalking(grid[row + 1][column])) {
Step bottom = new Step(row + 1, column, walked, this);
if (!walked.contains(bottom)) {
bottom.obstaclesCount = this.obstaclesCount;
count += bottom.walking(grid);
}
}
}
if (column > 0) {
if (canWalking(grid[row][column - 1])) {
Step left = new Step(row, column - 1, walked, this);
if (!walked.contains(left)) {
left.obstaclesCount = this.obstaclesCount;
count += left.walking(grid);
}
}
}
if ((column + 1) < grid[0].length) {
if (canWalking(grid[row][column + 1])) {
Step right = new Step(row, column + 1, walked, this);
if (!walked.contains(right)) {
right.obstaclesCount = this.obstaclesCount;
count += right.walking(grid);
}
}
}
}
return count;
}
@Override
public boolean equals(Object obj) {
if (obj instanceof Step) {
Step step = (Step) obj;
if (step.row == this.row && step.column == this.column)
return true;
}
return false;
}
}
public int uniquePathsIII(int[][] grid) {
int rowMax = grid.length, columnMax = grid[0].length;
int obstaclesCount = 0;
Step start = null;
for (int i = 0; i < rowMax; i++) {
for (int j = 0; j < columnMax; j++) {
if (grid[i][j] == 1)
start = new Step(i, j);
if (grid[i][j] == -1)
obstaclesCount++;
}
}
if (start != null) {
start.obstaclesCount = obstaclesCount;
return start.walking(grid);
}
return 0;
}
}
|