Merge pull request #2091 from CodingTestStudy2/정진영

[정진영] Day26

Author: github-actions[bot]

leetcode3/정진영/935. Knight Dialer

@@ -0,0 +1,55 @@
+/**
+ * @param {number} n
+ * @return {number}
+ */
+var knightDialer = function(n) {
+    /*
+    0 → 4, 6
+    1 → 6, 8
+    2 → 7, 9
+    3 → 4, 8
+    4 → 0, 3, 9
+    5 → x
+    6 → 0, 1, 7
+    7 → 2, 6
+    8 → 1, 3
+    9 → 2, 4
+     */
+
+    // dp
+    const MOD = 1000000007;
+
+    const moves = [
+        [4, 6],       // 0
+        [6, 8],       // 1
+        [7, 9],       // 2
+        [4, 8],       // 3
+        [0, 3, 9],    // 4
+        [],            // 5
+        [0, 1, 7],    // 6
+        [2, 6],       // 7
+        [1, 3],       // 8
+        [2, 4]        // 9
+    ];
+
+    // 길이 1일 때는 각 숫자에서 시작하는 경우가 1개씩
+    let dp = Array(10).fill(1);
+
+    for (let len = 2; len <= n; len++) {
+        const next = Array(10).fill(0);
+
+        for (let digit = 0; digit < 10; digit++) {
+            for (const nextDigit of moves[digit]) {
+                next[nextDigit] =
+                    (next[nextDigit] + dp[digit]) % MOD;
+            }
+        }
+
+        dp = next;
+    }
+
+    return dp.reduce(
+        (sum, count) => (sum + count) % MOD,
+        0
+    );
+};