diff --git a/20240823/十四届蓝桥比赛/数独填数.cpp b/20240823/十四届蓝桥比赛/数独填数.cpp
index e92b354..7cc258b 100644
--- a/20240823/十四届蓝桥比赛/数独填数.cpp
+++ b/20240823/十四届蓝桥比赛/数独填数.cpp
@@ -1,32 +1,76 @@
-//NOT DONE
 #include<bits/stdc++.h>
 using namespace std;
 
+int m[10][10];
+bool h_is_used[10][10],l_is_used[10][10],t_is_used[4][4][10];
+
 #ifdef OI
 #define DB(code){code}
+#define PV(v){cout<<#v<<" : "<<(v)<<endl;}
 #else
 #define DB(code)
+#define PV(v)
 #endif
 
-int m[10][10];
-// bool check_h[10][10],check_l[10][10],check_yx[20][10],check_zx[20][10];
-// bool check_all(int x,int y,int num){
-//     if(check_h[x][num]){
-//         return false;
-//     }
-//     if(check_l[y][num]){
-//         return false;
-//     }
-//     if(check_yx[x-y+8][num]){
-//         return false;
-//     }
-//     if(check_zx[])
-// }
+void dfs(int x,int y);
+optional<pair<int,int>> find_next(int x,int y);
+
+int main(){
+    for(int i=1;i<=9;i++){
+        string str;
+        getline(cin,str);
+        for(int j=1;j<=9;j++){
+            if(str[j-1]=='.'){
+                m[i][j]=-1;
+            }else{
+                m[i][j]=str[j-1]-'0';
+                h_is_used[i][m[i][j]]=true;
+                l_is_used[j][m[i][j]]=true;
+                t_is_used[i/3+1][j/3+1][m[i][j]]=true;
+            }
+        }
+    }
+    DB(
+        for(int i=1;i<=9;i++){
+            for(int j=1;j<=9;j++){
+                cout<<m[i][j]<<"\t";
+            }
+            cout<<endl;
+        }
+    )
+    auto find = find_next(1, 1);
+    if(find.has_value()==false){
+        for(int i=1;i<=9;i++){
+            for(int j=1;j<=9;j++){
+                cout<<m[i][j];
+            }
+            cout<<endl;
+        }
+        exit(0);
+    }
+    dfs(find->first, find->second);
+}
+
+optional<pair<int,int>> find_next(int x,int y){
+    for (int j=y+1; j<=9; j++) {
+        if(m[x][j]==-1){
+            return make_optional<pair<int,int>>({x,j});
+        }
+    }
+    for(int i=x+1;i<=9;i++){
+        for(int j=1;j<=9;j++){
+            if(m[i][j]==-1){
+                return make_optional<pair<int,int>>({i,j});
+            }
+        }
+    }
+    return nullopt;
+}   
 
-// bool check(int x,int y,int num);
-bool check(int x,int y,int num);
 void dfs(int x,int y){
-    if(x==9&&y==9){
+    DB(PV(x)PV(y)cout<<endl;)
+    auto find = find_next(x, y);
+    if(find.has_value()==false){
         for(int i=1;i<=9;i++){
             for(int j=1;j<=9;j++){
                 cout<<m[i][j];
@@ -36,69 +80,19 @@ void dfs(int x,int y){
         exit(0);
     }
     for(int i=1;i<=9;i++){
-
-    }
-}
-
-int main(){
-    for(int i=1;i<=9;i++){
-        char ch[15];
-        cin.getline(ch,10);
-        for(int j=1;j<=9;j++){
-            if(ch[j-1]=='.'){
-                m[i][j]=-1;
-            }else{
-                m[i][j]=ch[j-1]-'0';
-            }
+        if(h_is_used[x][i]||l_is_used[y][i]||t_is_used[x/3+1][y/3+1][i]){
+            continue;
         }
-    }
-    DB(
-        for(int i=1;i<=9;i++){
-            for(int j=1;j<=9;j++){
-                cout<<m[i][j]<<" ";
-            }
-            cout<<endl;
-        }
-    )
-    
-}
+        h_is_used[x][i]=true,
+        l_is_used[y][i]=true,
+        t_is_used[x/3+1][y/3+1][i]=true;
+        m[x][y]=i;
 
-// void dfs(int x,int y){
+        dfs(find->first, find->second);
 
-// }
-
-bool check(int x,int y,int num){
-    for(int i=1;i<=9;i++){
-        if(m[i][y]==num){
-            return false;
-        }
+        h_is_used[x][i]=false;
+        l_is_used[y][i]=false;
+        t_is_used[x/3+1][y/3+1][i]=false;
+        m[x][y]=-1;
     }
-    for(int i=1;i<=9;i++){
-        if(m[x][i]==num){
-            return false;
-        }
-    }
-    for(int i=x+1,j=y+1;i<=9&&j<=9;i++,j++){
-        if(m[i][j]==num){
-            return false;
-        }
-    }
-    for(int i=x-1,j=y-1;i>=1&&j>=1;i--,j--){
-        if(m[i][j]==num){
-            return false;
-        }
-    }
-    return true;
-}
-
-/*
-17.5..8..
-.52.1....
-.....759.
-.8...94.3
-.197.4..8
-7......15
-4.1...6..
-3...2..59
-...96..3.
-*/
\ No newline at end of file
+}
\ No newline at end of file
diff --git a/out.txt b/out.txt
new file mode 100644
index 0000000..3a5bd8d
Binary files /dev/null and b/out.txt differ
diff --git a/xmake.lua b/xmake.lua
index 08ec4d7..7f0e66f 100644
--- a/xmake.lua
+++ b/xmake.lua
@@ -1,6 +1,7 @@
 add_rules("mode.debug","mode.release")
 if is_mode("debug") then 
-    add_cxxflags("-O2","-DOI")
+    -- add_cxxflags("-O2","-DOI")
+    add_cxxflags("-DOI")
 end 
 set_languages("c++17")