From f0ead9ce242166260520353f4e3b9bc3476e3286 Mon Sep 17 00:00:00 2001
From: songyc macbook <gitea@gitea>
Date: Sat, 27 Sep 2025 21:18:26 +0900
Subject: [PATCH] 20250927 baekjoon

---
 code_study/Baekjoon/ts/1987.ts | 35 ++++++++++++++++++++++++++++++++++
 1 file changed, 35 insertions(+)
 create mode 100644 code_study/Baekjoon/ts/1987.ts

diff --git a/code_study/Baekjoon/ts/1987.ts b/code_study/Baekjoon/ts/1987.ts
new file mode 100644
index 0000000..045b9b1
--- /dev/null
+++ b/code_study/Baekjoon/ts/1987.ts
@@ -0,0 +1,35 @@
+export {};
+
+const input: string[] = require("fs").readFileSync(0).toString().trim().split('\n');
+const [R, C]: number[] = input[0].split(' ').map(Number);
+
+let board: string[][] = [];
+for(let i=1; i<=R; i++) {
+    board.push(input[i].split(''));
+}
+
+let alphabet: boolean[] = new Array(26).fill(false);
+alphabet[board[0][0].charCodeAt(0) - 65] = true;
+let maxStep: number = 1;
+
+const dx: number[] = [1,-1,0,0];
+const dy: number[] = [0,0,1,-1];
+
+const dfs = ([cx, cy, cs]: number[]) => {
+    maxStep = Math.max(cs, maxStep);
+
+    for(let i=0; i<4; i++) {
+        const nx = cx + dx[i];
+        const ny = cy + dy[i];
+
+        if(0<=nx && nx<C && 0<=ny && ny<R && !alphabet[board[ny][nx].charCodeAt(0) - 65]) {
+            alphabet[board[ny][nx].charCodeAt(0) - 65] = true;
+            dfs([nx,ny,cs+1]);
+            alphabet[board[ny][nx].charCodeAt(0) - 65] = false;
+        }
+    }
+}
+
+dfs([0,0,1]);
+
+console.log(maxStep);
\ No newline at end of file