Create available-captures-for-rook.cpp

Author: kamyu104

C++/available-captures-for-rook.cpp

@@ -0,0 +1,35 @@
+// Time:  O(1)
+// Space: O(1)
+
+class Solution {
+public:
+    int numRookCaptures(vector<vector<char>>& board) {
+        static vector<pair<int, int>> directions{{0, 1}, {1, 0}, {0, -1}, {-1, 0}};
+
+        int r = -1, c = -1;
+        for (int i = 0; i < 8 && r == -1; ++i) {
+            for (int j = 0; j < 8; ++j) {
+                if (board[i][j] == 'R') {
+                    tie(r, c) = make_pair(i, j);
+                    break;
+                }
+            }
+        }
+
+        int result = 0;
+        for(const auto& d : directions) {
+            int nr, nc;
+            tie(nr, nc) = make_pair(r + d.first, c + d.second);
+            while (0 <= nr && nr < 8 && 0 <= nc && nc < 8) {
+                if (board[nr][nc] == 'p') {
+                    ++result;
+                }
+                if (board[nr][nc] != '.') {
+                    break;
+                }
+                tie(nr, nc) = make_pair(nr + d.first, nc + d.second);
+            }
+        }
+        return result;
+    }
+};