6161 <li>只有一个格子上存在 <code>board[i][j] == 'R'</code></li>
6262</ol >
6363
64-
6564## 解法
6665
6766<!-- 这里可写通用的实现逻辑 -->
7776``` python
7877class Solution :
7978 def numRookCaptures (self board : List[List[str ]]) -> int :
80-
81- def search (board , i , j , direction ):
82- while i >= 0 and i < 8 and j >= 0 and j < 8 :
83- if board[i][j] == ' B' return 0
84- if board[i][j] == ' p' return 1
85- i += direction[0 ]
86- j += direction[1 ]
87- return 0
88- directions = [(- 1 , 0 ), (1 , 0 ), (0 , - 1 ), (0 , 1 )]
89- res = 0 ;
90- for i in range (8 ):
91- for j in range (8 ):
79+ x, y, n = 0 , 0 , 8
80+ for i in range (n):
81+ for j in range (n):
9282 if board[i][j] == ' R'
93- for direction in directions:
94- res += search(board, i, j, direction)
95- return res
83+ x, y = i, j
84+ break
85+ ans = 0
86+ for a, b in [[0 , - 1 ], [0 , 1 ], [- 1 , 0 ], [1 , 0 ]]:
87+ i, j = x, y
88+ while 0 <= i + a < n and 0 <= j + b < n and board[i + a][j + b] != ' B'
89+ i, j = i + a, j + b
90+ if board[i][j] == ' p'
91+ ans += 1
92+ break
93+ return ans
9694```
9795
9896### ** Java**
@@ -102,30 +100,112 @@ class Solution:
102100``` java
103101class Solution {
104102 public int numRookCaptures (char [][] board ) {
105- int [][] directions = { {- 1 , 0 }, {1 , 0 }, {0 , - 1 }, {0 , 1 } };
106- int res = 0 ;
107- for (int i = 0 ; i < 8 ; ++ i) {
108- for (int j = 0 ; j < 8 ; ++ j) {
103+ int [] pos = find(board);
104+ int ans = 0 , n = 8 ;
105+ int [][] dirs = new int [][]{{0 , - 1 }, {0 , 1 }, {- 1 , 0 }, {1 , 0 }};
106+ for (int [] dir : dirs) {
107+ int x = pos[0 ], y = pos[1 ], a = dir[0 ], b = dir[1 ];
108+ while (x + a >= 0 && x + a < n && y + b >= 0 && y + b < n && board[x + a][y + b] != ' B'
109+ x += a;
110+ y += b;
111+ if (board[x][y] == ' p'
112+ ++ ans;
113+ break ;
114+ }
115+ }
116+ }
117+ return ans;
118+ }
119+
120+ private int [] find (char [][] board ) {
121+ int n = 8 ;
122+ for (int i = 0 ; i < n; ++ i) {
123+ for (int j = 0 ; j < n; ++ j) {
109124 if (board[i][j] == ' R'
110- for (int [] direction : directions) {
111- res += search(board, i, j, direction);
112- }
113- return res;
125+ return new int []{i, j};
126+ }
127+ }
128+ }
129+ return null ;
130+ }
131+ }
132+ ```
133+
134+ ### ** C++**
135+
136+ ``` cpp
137+ class Solution {
138+ public:
139+ int numRookCaptures(vector<vector<char >>& board) {
140+ vector<int > pos = find(board);
141+ int ans = 0, n = 8;
142+ vector<vector<int >> dirs = {{0, 1}, {0, - 1}, {1, 0}, {-1, 0}};
143+ for (auto& dir : dirs)
144+ {
145+ int x = pos[ 0] , y = pos[ 1] , a = dir[ 0] , b = dir[ 1] ;
146+ while (x + a >= 0 && x + a < n && y + b >= 0 && y + b < n && board[ x + a] [ y + b ] != 'B')
147+ {
148+ x += a;
149+ y += b;
150+ if (board[ x] [ y ] == 'p')
151+ {
152+ ++ans;
153+ break;
114154 }
115155 }
116156 }
117- return res ;
157+ return ans ;
118158 }
119159
120- private int search (char [][] board , int i , int j , int [] direction ) {
121- while (i >= 0 && i < 8 && j >= 0 && j < 8 ) {
122- if (board[i][j] == ' B' return 0 ;
123- if (board[i][j] == ' p' return 1 ;
124- i += direction[0 ];
125- j += direction[1 ];
160+ vector<int> find(vector<vector<char>>& board) {
161+ int n = 8;
162+ for (int i = 0; i < n; ++i)
163+ {
164+ for (int j = 0; j < n; ++j)
165+ {
166+ if (board[i][j] == 'R')
167+ {
168+ return {i, j};
169+ }
170+ }
126171 }
127- return 0 ;
172+ return {} ;
128173 }
174+ };
175+ ```
176+
177+ ### ** Go**
178+
179+ ``` go
180+ func numRookCaptures (board [][]byte ) int {
181+ n := 8
182+
183+ find := func () []int {
184+ for i := 0 ; i < n; i++ {
185+ for j := 0 ; j < n; j++ {
186+ if board[i][j] == ' R'
187+ return []int {i, j}
188+ }
189+ }
190+ }
191+ return []int {}
192+ }
193+
194+ pos := find ()
195+ ans := 0
196+ dirs := [4 ][2 ]int {{0 , -1 }, {0 , 1 }, {1 , 0 }, {-1 , 0 }}
197+ for _ , dir := range dirs {
198+ x , y , a , b := pos[0 ], pos[1 ], dir[0 ], dir[1 ]
199+ for x+a >= 0 && x+a < n && y+b >= 0 && y+b < n && board[x+a][y+b] != ' B'
200+ x += a
201+ y += b
202+ if board[x][y] == ' p'
203+ ans++
204+ break
205+ }
206+ }
207+ }
208+ return ans
129209}
130210```
131211
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