add solution for word-search

Author: Hyeri1ee

word-search/Hyeri1ee.java

@@ -0,0 +1,73 @@
+import java.util.*;
+
+
+class Solution {
+
+    //상,하,좌,우
+    static int[] dx = {0,1,-1,0};
+    static int[] dy = {1,0,0,-1};
+
+    static int m, n;
+
+    static boolean result; //exist 함수가 호출될때마다 초기화해야함
+    static char[][] map; //지역변수 board 저장용
+    static String w; //word 저장용
+    public boolean exist(char[][] board, String word) {
+
+        result=false;
+
+        m = board.length;
+        n = board[0].length;
+
+        w = word;
+        //map <- board
+        map = new char[m][n];
+        for(int i =0; i<m;i++){
+            for(int j=0; j< n; j++){
+                map[i][j] = board[i][j];
+            }
+        }
+
+
+        for(int x =0 ; x < m; x++){
+            for(int y =0 ; y < n ;y++){
+                dfs(x, y , 0); //위치 x,y, word에 대한 찾는 인덱스
+                if (result) return result;
+            }
+        }
+
+
+
+        //기본 
+        return result;
+    }
+
+    private static void dfs(int x, int y, int idx){
+        //종료조건
+        if (result) return;
+
+        if (!checkin(x, y) || map[x][y] != w.charAt(idx)) return;
+
+        //마지막 문자일때 종료
+        if (idx == w.length() - 1){
+            result = true;
+            return;
+        }   
+
+        char temp = map[x][y];
+        map[x][y] = '#';
+
+        for(int i = 0; i < 4; i++){
+            dfs(x + dx[i], y + dy[i], idx + 1);
+        }
+
+        map[x][y] = temp;
+            
+    }
+
+    //map 내부 checkin 함수 정의
+    private static boolean checkin(int x, int y){
+        return x >= 0 && x < m && y >= 0 && y < n;
+    }
+}
+