@@ -149,7 +149,63 @@ public:
149149
150150### Java
151151
152- 深度优先遍历版本:
152+ 深度优先遍历(没有终止条件 + 空間優化(淹沒島嶼,沒有使用visited數組))
153+ ``` java
154+ // DFS
155+ class Solution {
156+ int count = 0 ;
157+ int [][] dir = {
158+ {0 , 1 },
159+ {1 , 0 },
160+ {- 1 , 0 },
161+ {0 , - 1 }
162+ };
163+ private void dfs (int [][] grid , int x , int y ){
164+ if (grid[x][y] == 0 )
165+ return ;
166+ 167+ grid[x][y] = 0 ;
168+ count++ ;
169+ 170+ for (int i = 0 ; i < 4 ; i++ ){
171+ int nextX = x + dir[i][0 ];
172+ int nextY = y + dir[i][1 ];
173+ 174+ if (nextX < 0 || nextY < 0 || nextX >= grid. length || nextY >= grid[0 ]. length)
175+ continue ;
176+ dfs(grid, nextX, nextY);
177+ }
178+ 179+ }
180+ 181+ public int numEnclaves (int [][] grid ) {
182+ for (int i = 0 ; i < grid. length; i++ ){
183+ if (grid[i][0 ] == 1 )
184+ dfs(grid, i, 0 );
185+ if (grid[i][grid[0 ]. length - 1 ] == 1 )
186+ dfs(grid, i, grid[0 ]. length - 1 );
187+ }
188+ // 初始化的時候,j 的上下限有調整過,必免重複操作。
189+ for (int j = 1 ; j < grid[0 ]. length - 1 ; j++ ){
190+ if (grid[0 ][j] == 1 )
191+ dfs(grid, 0 , j);
192+ if (grid[grid. length - 1 ][j] == 1 )
193+ dfs(grid, grid. length - 1 , j);
194+ }
195+ count = 0 ;
196+ 197+ for (int i = 1 ; i < grid. length - 1 ; i++ ){
198+ for (int j = 1 ; j < grid[0 ]. length - 1 ; j++ ){
199+ if (grid[i][j] == 1 )
200+ dfs(grid, i, j);
201+ }
202+ }
203+ return count;
204+ }
205+ }
206+ ```
207+ 208+ 深度优先遍历(没有终止条件)
153209
154210``` java
155211class Solution {
@@ -206,7 +262,7 @@ class Solution {
206262}
207263```
208264
209- 广度优先遍历版本:
265+ 广度优先遍历(使用visited數組)
210266
211267``` java
212268class Solution {
@@ -269,6 +325,72 @@ class Solution {
269325}
270326```
271327
328+ 廣度优先遍历(空間優化(淹沒島嶼,沒有使用visited數組))
329+ ``` java
330+ // BFS
331+ class Solution {
332+ int count = 0 ;
333+ int [][] dir = {
334+ {0 , 1 },
335+ {1 , 0 },
336+ {- 1 , 0 },
337+ {0 , - 1 }
338+ };
339+ private void bfs (int [][] grid , int x , int y ){
340+ Queue<Integer > que = new LinkedList<> ();
341+ que. offer(x);
342+ que. offer(y);
343+ count++ ;
344+ grid[x][y] = 0 ;
345+ 346+ while (! que. isEmpty()){
347+ int currX = que. poll();
348+ int currY = que. poll();
349+ 350+ for (int i = 0 ; i < 4 ; i++ ){
351+ int nextX = currX + dir[i][0 ];
352+ int nextY = currY + dir[i][1 ];
353+ 354+ if (nextX < 0 || nextY < 0 || nextX >= grid. length || nextY >= grid[0 ]. length)
355+ continue ;
356+ 357+ if (grid[nextX][nextY] == 1 ){
358+ que. offer(nextX);
359+ que. offer(nextY);
360+ count++ ;
361+ grid[nextX][nextY] = 0 ;
362+ }
363+ }
364+ }
365+ }
366+ 367+ public int numEnclaves (int [][] grid ) {
368+ for (int i = 0 ; i < grid. length; i++ ){
369+ if (grid[i][0 ] == 1 )
370+ bfs(grid, i, 0 );
371+ if (grid[i][grid[0 ]. length - 1 ] == 1 )
372+ bfs(grid, i, grid[0 ]. length - 1 );
373+ }
374+ for (int j = 1 ; j < grid[0 ]. length; j++ ){
375+ if (grid[0 ][j] == 1 )
376+ bfs(grid, 0 , j);
377+ if (grid[grid. length - 1 ][j] == 1 )
378+ bfs(grid, grid. length - 1 , j);
379+ }
380+ count = 0 ;
381+ for (int i = 1 ; i < grid. length - 1 ; i++ ){
382+ for (int j = 1 ; j < grid[0 ]. length - 1 ; j++ ){
383+ if (grid[i][j] == 1 )
384+ bfs(grid,i ,j);
385+ }
386+ }
387+ return count;
388+ }
389+ }
390+ 391+ 392+ ```
393+ 272394### Python
273395
274396深度优先遍历
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