[BOJ] 1987 알파벳 (G4)

Author: uiop5809

박예진/7주차/260209.cpp

@@ -0,0 +1,55 @@
+// https://www.acmicpc.net/problem/1987
+
+#include <bits/stdc++.h>
+using namespace std;
+
+/*
+  지금까지 지나온 모든칸 알파벳과 달라야함
+  1, 1 시작, 최대한 몇 칸 지나갈 수 있는지
+*/
+
+int R, C, res;
+char arr[21][21];
+bool visited[21][21];
+
+const int dx[] = {1, 0, -1, 0};
+const int dy[] = {0, -1, 0, 1};
+
+bool alpha[26];
+
+void dfs(int x, int y, int cnt){
+  res = max(res, cnt);
+
+  visited[x][y] = true;
+  alpha[arr[x][y] - 'A'] = true; 
+
+  for(int i = 0; i < 4; i++){
+    int nx = x + dx[i];
+    int ny = y + dy[i];
+
+    if (nx < 1 || nx > R || ny < 1 || ny > C) continue;
+    if (!visited[nx][ny] && !alpha[arr[nx][ny] - 'A']) {
+      dfs(nx, ny, cnt + 1);
+    }
+  }
+
+  visited[x][y] = false;
+  alpha[arr[x][y] - 'A'] = false;
+}
+
+int main() {
+  ios_base::sync_with_stdio(false);
+  cin.tie(NULL); cout.tie(NULL);
+
+  cin >> R >> C;
+  for(int i = 1; i <= R; i++){
+    for(int j = 1; j <= C; j++){
+      cin >> arr[i][j];
+    }
+  }
+
+  dfs(1, 1, 1);
+  cout << res;
+
+  return 0;
+}