update

src/P1219/P1219.cpp

@@ -0,0 +1,48 @@
+#include <iostream>
+#include <stdexcept>
+
+using ll = long long;
+
+auto &is = std::cin;
+auto &os = std::cout;
+
+template<class T,size_t size>
+struct greater_array{
+    T arr[size*2];
+    T&operator[](ll n)noexcept{
+        return arr[n+size];
+    }
+};
+
+const ll max_n {13+5};
+ll n;
+greater_array<bool, max_n*3> l,zx,yx;
+ll ans[max_n], sum;
+
+
+void dfs(const ll x)noexcept{
+    if(x>n){
+        sum++;
+        if(sum<=3){
+            for(ll i{1};i<=n;i++){
+                os<<ans[i]<<' ';
+            }
+            os<<'\n';
+        }
+        return;
+    }
+    for(ll j{1};j<=n;j++){
+        if(l[j]||zx[x+j]||yx[x-j])continue;
+        ans[x] = j;
+        l[j]=zx[x+j]=yx[x-j]=true;
+        dfs(x+1);
+        l[j]=zx[x+j]=yx[x-j]=false;
+    }
+    return;
+}
+
+int main()noexcept{
+    is>>n;
+    dfs(1);
+    os<<sum<<'\n';
+}