Merge pull request #23 from algorithm-cote-study/yeji/leetCode

feat : leetCode Graph활용 문제풀이

Author: seunggulee1007

.idea/sonarlint/issuestore/index.pb

@@ -25,3 +25,5 @@
 ## Graph
 
 - [200. Number of Islands](https://leetcode.com/problems/number-of-islands/description/)
+- [1091. Shortest Path in Binary Matrix](https://leetcode.com/problems/shortest-path-in-binary-matrix/)
+- [841. Keys and Rooms](https://leetcode.com/problems/keys-and-rooms/description/)

src/main/java/sgyj/leetcode/Readme.md

@@ -0,0 +1,50 @@
+package sgyj.leetcode.yeji.section5;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+
+// 1091. Shortest Path in Binary Matrix
+public class Solution1091 {
+    private static int[] dx = {-1,1,0,0,1,1,-1,-1};
+    private static int[] dy = {0,0,-1,1,1,-1,-1,1};
+    private static boolean[][] visited;
+
+    public static int shortestPathBinaryMatrix(int[][] grid) {
+        int answer = -1;
+        int n = grid.length;
+        visited = new boolean[n][n];
+
+        Deque<Location> q = new ArrayDeque<>();
+        if(grid[0][0] != 0) return -1;
+        visited[0][0] = true;
+        q.offer( new Location(0,0,1 ) );
+        while ( !q.isEmpty() ){
+            int len = q.size();
+            for(int i=0; i<len; i++){
+                Location curNode = q.poll();
+                if(curNode.x == n-1 && curNode.y == n-1) {
+                    answer = curNode.len;
+                    break;
+                }
+                for(int d=0; d<dx.length; d++){
+                    int x = curNode.x + dx[d];
+                    int y = curNode.y + dy[d];
+                    if(x>=0 && x<n && y>=0 && y<n && !visited[x][y] && grid[x][y] == 0){
+                        visited[x][y] = true;
+                        q.offer( new Location( x,y , curNode.len+1 ) );
+                    }
+                }
+            }
+        }
+        return answer;
+    }
+
+    public static void main ( String[] args ) {
+        int[][] grid = {
+//            [[0,0,0],[1,1,0],[1,1,0]]
+            {0,0,0},{1,1,0},{1,1,0}
+        };
+
+        System.out.println(shortestPathBinaryMatrix( grid ));
+    }
+}

src/main/java/sgyj/leetcode/yeji/section5/Solution1091.java

@@ -66,8 +66,16 @@ class  Location{
     int x;
     int y;
 
+    int len;
+
     Location(int x, int y){
         this.x = x;
         this.y = y;
     }
+
+    Location(int x, int y, int len){
+        this.x = x;
+        this.y = y;
+        this.len = len;
+    }
 }

src/main/java/sgyj/leetcode/yeji/section5/Solution200.java

@@ -0,0 +1,33 @@
+package sgyj.leetcode.yeji.section5;
+
+import java.util.ArrayDeque;
+import java.util.Deque;
+import java.util.List;
+
+// 841. Keys and Rooms
+public class Solution841 {
+    private static boolean[] visited;
+
+    public boolean canVisitAllRooms(List<List<Integer>> rooms) {
+        int n = rooms.size();
+        visited = new boolean[n];
+        Deque<Integer> q = new ArrayDeque<>();
+        q.offer(0);
+        visited[0] = true;
+        while(!q.isEmpty()){
+            int curNode = q.poll();
+            for(int i=0; i<rooms.get(curNode).size(); i++){
+                int target = rooms.get(curNode).get(i);
+                if(!visited[target]){
+                    q.offer(target);
+                    visited[target] = true;
+                }
+            }
+        }
+
+        for(boolean v : visited){
+            if(!v) return false;
+        }
+        return true;
+    }
+}