// time O(n * m * 4)
// space O(n * m)
class DFS {
public int movingCount(int m, int n, int k) {
int count = 0;
boolean[][] visited = new boolean[m][n];
dfs(m, n, 0, 0, k, visited);
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (visited[i][j]) {
count++;
}
}
}
return count;
}
void dfs(int m, int n, int row, int col, int k, boolean[][] visited) {
if (row < 0 || row >= m || col < 0 || col >= n) {
return;
}
if (visited[row][col]) {
return;
}
if (count(row) + count(col) > k) {
return;
}
if (row == m - 1 && col == n - 1) {
visited[row][col] = true;
return;
}
visited[row][col] = true;
dfs(m, n, row + 1, col, k, visited);
dfs(m, n, row - 1, col, k, visited);
dfs(m, n, row, col + 1, k, visited);
dfs(m, n, row, col - 1, k, visited);
}
int count(int n) {
int sum = 0;
while (n != 0) {
sum += n % 10;
n /= 10;
}
return sum;
}
}
// time O(n * m * 4)
// espace O(n * m)
class BFS {
public int movingCount(int m, int n, int k) {
if (k == 0) {
return 1;
}
Queue<int[]> q = new LinkedList<>();
boolean[][] vis = new boolean[m][n];
q.offer(new int[] { 0, 0 });
int ans = 0;
while (!q.isEmpty()) {
int[] cell = q.poll();
int x = cell[0], y = cell[1];
if (!inArea(x, y, vis) || vis[x][y] || sum(x) + sum(y) > k) {
continue;
}
vis[x][y] = true;
q.offer(new int[] { x - 1, y });
q.offer(new int[] { x + 1, y });
q.offer(new int[] { x, y + 1 });
q.offer(new int[] { x, y - 1 });
ans++;
}
return ans;
}
boolean inArea(int row, int col, boolean[][] vis) {
return row >= 0 && row < vis.length && col >= 0 && col < vis[0].length;
}
int sum(int x) {
int res = 0;
while (x != 0) {
res += x % 10;
x /= 10;
}
return res;
}
}
https://leetcode-cn.com/problems/ji-qi-ren-de-yun-dong-fan-wei-lcof/
思路
[x] 刷15mins
[x] 刷5mins