Update and rename 361.-Bomb-Enemy.java to 361. Bomb Enemy.java

Author: futurus

Diff for: 361. Bomb Enemy.java

@@ -0,0 +1,84 @@
+public class Solution {
+    public int maxKilledEnemies(char[][] grid) {
+        int maxKill = 0;
+        
+        // find empty cells
+        for (int r = 0; r < grid.length; r++) {
+            for (int c = 0; c < grid[r].length; c++) {
+                int kill = 0;
+                if (grid[r][c] == '0') {
+                    int row = r;
+                    while (--row >= 0 && grid[row][c] != 'W') {
+                        if (grid[row][c] == 'E') kill++;
+                    }
+                    row = r;
+                    while (++row < grid.length && grid[row][c] != 'W') {
+                        if (grid[row][c] == 'E') kill++;
+                    }
+                    
+                    int col = c;                    
+                    while (--col >= 0 && grid[r][col] != 'W') {
+                        if (grid[r][col] == 'E') kill++;
+                    }
+                    col = c;
+                    while (++col < grid[r].length && grid[r][col] != 'W') {
+                        if (grid[r][col] == 'E') kill++;
+                    }
+                    if (kill > maxKill) {
+                        maxKill = kill;
+                    }
+                }
+            }
+        }
+        return maxKill;
+    }
+}
+
+
+// DP-ish solution for ref: https://discuss.leetcode.com/topic/50374/java-dp-solultion-o-mn-time-o-mn-space-beats-90
+public class Solution {
+    public int maxKilledEnemies(char[][] grid) {
+        if (grid == null || grid.length == 0 || grid[0].length == 0) return 0;
+
+        int m = grid.length;
+        int n = grid[0].length;
+        int[][] dp = new int[m][n];
+
+        // from left to right
+        for (int i = 0; i < m; i++) {
+            int current = 0;
+            for (int j = 0; j < n; j++) 
+                current = process(grid, dp, i, current, j);
+        }
+        // from top to bottom
+        for (int j = 0; j < n; j++) {
+            int current = 0;
+            for (int i = 0; i < m; i++) 
+                current = process(grid, dp, i, current, j);
+        }
+        // from right to left
+        for (int i = 0; i < m; i++) {
+            int current = 0;
+            for (int j = n - 1; j >= 0; j--) 
+                current = process(grid, dp, i, current, j);
+        }
+        int ans = 0;
+        // from bottom to top
+        for (int j = 0; j < n; j++) {
+            int current = 0;
+            for (int i = m - 1; i >= 0; i--) {
+                current = process(grid, dp, i, current, j);
+                if (grid[i][j] == '0')  ans = Math.max(ans, dp[i][j]);
+            }
+        }
+
+        return ans;
+    }
+
+    private int process(char[][] c, int[][] dp, int i, int current, int j) {
+        if (c[i][j] == 'W') current = 0;
+        if (c[i][j] == 'E') current++;
+        dp[i][j] += current;
+        return current;
+    }
+}