Add #7 등굣길 - 지선아

dp/등굣길/지선아.java

@@ -0,0 +1,30 @@
+class Solution {
+    private static final int NUM = 1000000007;
+    int[][] dp;
+    public int solution(int m, int n, int[][] puddles) {
+        dp = new int[m][n];
+        // 초기값 설정
+        for (int i = 0; i < m; i++) {
+            for (int j = 0; j < n; j++) {
+                dp[i][j] = -1;
+            }
+        }
+        // 웅덩이 설정
+        for (int[] puddle : puddles) {
+            dp[puddle[0] - 1][puddle[1] - 1] = 0;
+        }
+        dp[0][0] = 1;
+        return dfs(m-1, n-1);
+    }
+
+    public int dfs(int x, int y) {
+        if (x < 0 || y < 0) {
+            return 0;
+        }
+        if (dp[x][y] != -1) {
+            return dp[x][y];
+        }
+        dp[x][y] = (dfs(x - 1, y) + dfs(x, y-1)) % NUM;
+        return dp[x][y];
+    }
+}