[BOJ] 2239 스도쿠 (G4)

Author: uiop5809

박예진/0주차/백트래킹/2239.cpp

@@ -0,0 +1,69 @@
+#include <iostream>
+#include <vector>
+using namespace std;
+
+struct Node {
+    int x, y;
+};
+
+char arr[10][10];
+bool rows[10][10];
+bool cols[10][10];
+bool board[10][10];
+vector<Node> zeros;
+
+int getBoardIdx(int r, int c) {
+    return (r / 3) * 3 + (c / 3);
+}
+
+void dfs(int idx){
+    if (idx == zeros.size()) {
+        for (int i = 0; i < 9; i++) {
+            for (int j = 0; j < 9; j++) {
+                cout << arr[i][j];
+            }
+            cout << '\n';
+        }
+        exit(0);
+    }
+
+    int r = zeros[idx].x;
+    int c = zeros[idx].y;
+    int b = getBoardIdx(r, c);
+
+    for(int i = 1; i <= 9; i++){
+        // 행, 열, 9칸 다 검색
+        if (!rows[r][i] && !cols[c][i] && !board[b][i]) {
+            rows[r][i] = true;
+            cols[c][i] = true;
+            board[b][i] = true;
+            arr[r][c] = i + '0';
+            dfs(idx + 1);
+            arr[r][c] = '0';
+            rows[r][i] = false;
+            cols[c][i] = false;
+            board[b][i] = false;
+        }
+    }
+}
+
+int main() {
+  ios::sync_with_stdio(false);
+  cin.tie(0); cout.tie(0);
+
+  for(int i = 0; i < 9; i++){
+    for(int j = 0; j < 9; j++){
+        cin >> arr[i][j];
+        int num = arr[i][j] - '0'; 
+        if (num == 0) zeros.push_back({i, j});
+        else {
+            rows[i][num] = true;
+            cols[j][num] = true;
+            board[getBoardIdx(i, j)][num] = true;
+        }
+    }
+  }
+  dfs(0);
+
+  return 0;
+}