[염혜정] Day17

leetcode3/염혜정/576. Out of Boundary Paths.java

@@ -0,0 +1,32 @@
+// bfs + dp
+
+class Solution {
+    public int findPaths(int m, int n, int maxMove, int startRow, int startColumn) {
+        final int MOD = 1_000_000_007;
+        long[][] dp = new long[m][n];
+        dp[startRow][startColumn] = 1;
+        int count = 0;
+        int[][] dirs = {{1, 0}, {-1, 0}, {0, 1}, {0, -1}};
+
+        for (int move = 0; move < maxMove; move++) {
+            long[][] next = new long[m][n];
+            for (int i = 0; i < m; i++) {
+                for (int j = 0; j < n; j++) {
+                    if (dp[i][j] == 0) continue;
+                    for (int[] d : dirs) {
+                        int ni = i + d[0];
+                        int nj = j + d[1];
+                        if (ni < 0 || ni >= m || nj < 0 || nj >= n) {
+                            count = (int) ((count + dp[i][j]) % MOD);
+                        } else {
+                            next[ni][nj] = (next[ni][nj] + dp[i][j]) % MOD;
+                        }
+                    }
+                }
+            }
+            dp = next;
+        }
+
+        return count;
+    }
+}