Solve Problem 1293 - Shortest Path In Grid With Obstacles Elimination

Author: hieu

README.md

@@ -12,7 +12,7 @@
 ### Trie:
 ### Binary Search: [#](https://leetcode.com/discuss/interview-question/313216/)
 ### Minimax: 913
-### Matrix: 1368, 1292, 864
+### Matrix: 1368, 1292, 864, 1293
 
 # Favorite: 
 

src/contest/ReadMe.java

@@ -6,8 +6,8 @@ public class ReadMe {
 
     // tree:                1339[v]     1325[v]     1379[v]     1372[v]
     // graph:               997[v]      1361[v]     1043[v]     1387[~]
-    // dfs:                 1319[v]     1254[v]     1377[v]     1145
-    // bfs:                 1345[v]     1368[!]     1311[v]     1293
+    // dfs:                 1319[v]     1254[v]     1377[v]     1145[x]
+    // bfs:                 1345[v]     1368[!]     1311[v]     1293[x]
     // backtrack:           1307[!]     1239[v]     1219[v]     1291
     // dp:                  1349[!]     1340[v]     1367[v]     1388
     // divide & conquer:    932[!]      514         903[v]      327

src/graph/bfs/Problem1293_ShortestPathInGridWithObstaclesElimination.java

@@ -0,0 +1,42 @@
+package graph.bfs;
+
+import java.util.Arrays;
+import java.util.LinkedList;
+import java.util.Queue;
+
+public class Problem1293_ShortestPathInGridWithObstaclesElimination {
+
+    public int shortestPath(int[][] A, int K) {
+        int m = A.length, n = A[0].length;
+        if (m == 1 && n == 1) return A[0][0];
+        if (K > m-1+n-1) return m+n-2;
+
+        int dirs[][] = {{-1, 0}, {0, -1}, {1, 0}, {0, 1}};
+        int breaks[][] = new int[m][n];
+        for (int[] row: breaks) Arrays.fill(row, m+n-2);
+        breaks[0][0] = A[0][0];
+
+        Queue<int[]> queue = new LinkedList<>();
+        queue.offer(new int[] {0, 0});
+
+        int res = 0;
+        while (!queue.isEmpty()) {
+            int size = queue.size();
+            while (size-- > 0) {
+                int e[] = queue.poll(), i = e[0], j = e[1];
+                for (int[] d : dirs) {
+                    int x = i+d[0], y = j+d[1];
+                    if (x < 0 || x >= m || y < 0 || y >= n) continue;
+                    int b = breaks[i][j] + A[x][y];
+                    if (b > K || b >= breaks[x][y]) continue;
+                    if (x == m-1 && y == n-1) return res+1;
+                    queue.offer(new int[] {x, y});
+                    breaks[x][y] = b;
+                }
+            }
+            res++;
+        }
+
+        return -1;
+    }
+}