delete pics to save space

2.1604.cpp

@@ -0,0 +1,113 @@
+#include<bits/stdc++.h>
+using namespace std;
+
+//上 前
+//0  1
+
+//0 1 2 3
+//E B W R
+#define empty 0
+#define blue  1
+#define white 2
+#define red   3
+
+const int dx[4]={-1,1,0,0};
+const int dy[4]={0,0,1,-1};
+pair<int,int> a[5][5];
+int goal[5][5],ans;
+
+inline int other(int x,int y)
+{
+	return 6-(x+y);
+}
+inline void rotate_left_right(pair<int,int> &x)
+{
+	pair<int,int> temp=x;
+	x.first=other(temp.first,temp.second);
+	x.second=temp.second;
+}
+inline void rotate_up_down(pair<int,int> &x)
+{
+	pair<int,int> temp=x;
+	x.first=temp.second;
+	x.second=temp.first;
+}
+inline int diff()
+{
+	int cnt=0;
+	for (int i=1;i<=3;i++)
+		for (int j=1;j<=3;j++)
+			if (a[i][j].first!=goal[i][j])
+				cnt++;
+	return cnt;
+}
+
+void dfs(int dep,int prex,int prey)
+{
+	int differ=diff();
+	if(differ==0)
+	{
+		if(dep<ans) ans=dep;
+		return;
+	}
+	if(dep+differ>ans) return;
+	int x,y;
+	for(int i=1;i<=3;i++)
+		for(int j=1;j<=3;j++)
+			if(a[i][j].first==0)
+				x=i,y=j;
+	for(int i=0;i<4;i++)
+	{
+		int tx=x+dx[i],ty=y+dy[i];
+		if(tx>=1&&tx<=3&&ty>=1&&ty<=3&&!(tx==prex&&ty==prey))
+		{
+			pair<int,int> temp=a[tx][ty];
+			if (i>1)
+				rotate_left_right(a[tx][ty]);
+			else
+				rotate_up_down(a[tx][ty]);
+			swap(a[tx][ty],a[x][y]);
+			dfs(dep+1,x,y);
+			a[tx][ty]=temp;
+			a[x][y]={0,0};
+		}
+	}
+}
+
+int main()
+{
+#ifdef local
+	freopen("pro.in","r",stdin);
+#endif
+	ios::sync_with_stdio(0);
+	int x,y;
+	while(cin>>x>>y)
+	{
+		swap(x,y);
+		if(x==0&&y==0) break;
+		for(int i=1;i<=3;i++)
+			for(int j=1;j<=3;j++)
+			{
+				if(i==x&&y==j) a[i][j]={0,0};
+				else a[i][j]={2,3};
+			}
+		for(int i=1;i<=3;i++)
+			for(int j=1;j<=3;j++)
+			{
+				char c;
+				cin>>c;
+				goal[i][j]=empty;
+				switch(c)
+				{
+					case 'B':goal[i][j]=blue;break;
+					case 'W':goal[i][j]=white;break;
+					case 'R':goal[i][j]=red;break;
+				}
+			}
+		ans=31;
+		dfs(0,-1,-1);
+		if(ans>=31) cout<<-1<<endl;
+		else cout<<ans<<endl;
+	}
+	return 0;
+}