搜索练习题

100道题中，99道都可以通过搜索大法得分。只练好搜索，随随便便拿个二等奖，再学点其他的，一等奖马上到手

推荐几道难度适合的搜索题目，并附上当时我的代码。题目都在codevs中，下面是其编号

1. codevs1136 mayan游戏

   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #define L_L "%I64d"
   #define N 28
   using namespace std;
   int n;
   struct mayan{
   	int a[6][9];
   	int c[11];
   	int fa,x,y,choose;
   	void read(){
   		int i,j;
   		for(i=0;i<=10;i++)
   		c[i]=0;
   		for(i=1;i<=5;i++){
   			for(j=1;;j++){
   			scanf("%d",&a[i][j]);
   			if(!a[i][j])break;
   			c[a[i][j]]++;
   			}
   		}
   	}
   	void print(){
   		printf("map%d %d %d\n",x,y,choose);
   		int i,j;
   		for(i=1;i<=5;i++){
   			for(j=1;j<=7;j++)
   			printf("%d ",a[i][j]);
   			printf("\n");
   		}
   	}
   	void down(){
   		int i,j,k;
   		for(i=1;i<=5;i++){ 
   		k=0;
   		for(j=1;j<=7;j++)
   		if(a[i][j])
   		a[i][++k]=a[i][j];
   		for(k++;k<=7;k++)
   		a[i][k]=0;
   		} 
   	} 
   	void cut(){
   		while(1){
   		int d[6][9]={};
   		bool flag=false;
   		int i,j,k;
   		for(i=1;i<=5;i++)
   		for(j=1;j<=7;j++)
   		if(a[i][j]){
   			for(k=0;a[i][j+k]&&a[i][j+k]==a[i][j]&&j+k<=7;k++);
   			if(k>2)
   			{
   			for(k--;k>=0;k--)d[i][j+k]=1;
   		    flag=true;
   			}
   			for(k=0;a[i+k][j]&&a[i+k][j]==a[i][j]&&i+k<=5;k++);
   			if(k>2){
   				for(k--;k>=0;k--)d[i+k][j]=1;
   				flag=true;
   			}
   		}
   		for(i=1;i<=5;i++){
   			k=0;
   		for(j=1;j<=7;j++)
   			 if(d[i][j]&&a[i][j])
   			{c[a[i][j]]--;a[i][j]=0;} 
   		 down();
   		}
   		if(!flag)
   		 return;
   		}
   	}
   }stack[10];
   bool flag=false;
   inline void DFS(int dep){
   	int i,x,y;
   	
   	
      	for(i=1;i<=10;i++)
   	if(stack[dep].c[i]>0&&stack[dep].c[i]<3)
   	return;
   	if(dep==n){
   		for(i=1;i<=10;i++)
   		if(stack[dep].c[i])return;
   		flag=true;
   		return;
   	}
   	 for(x=1;x<=5;x++)
   	 for(y=1;y<=7;y++)if(stack[dep].a[x][y]){
   	 	if(x!=5){
   	 		stack[dep+1]=stack[dep];
   	 		stack[dep+1].x=x;stack[dep+1].y=y;
   	 		stack[dep+1].choose=1;
   	 		swap(stack[dep+1].a[x][y],stack[dep+1].a[x+1][y]);
   	 		stack[dep+1].down();
   	 		stack[dep+1].cut();
   	 	
   	 		DFS(dep+1);
   	 		if(flag)return;
   		 }
   		 if(x!=1&&!stack[dep].a[x-1][y]){
   		 	
   	 		stack[dep+1]=stack[dep];
   	 		stack[dep+1].x=x;stack[dep+1].y=y;
   	 		stack[dep+1].choose=-1;
   	 		swap(stack[dep+1].a[x][y],stack[dep+1].a[x-1][y]);
   	 		stack[dep+1].down();
   			 stack[dep+1].cut();
   			
   			 DFS(dep+1);
   	 		if(flag)return;
   		 }
   	 }
   }
   void work(){
   	scanf("%d",&n);
   	stack[0].read();
   	DFS(0);
   	if(!flag){
   		printf("-1\n");return;
   	}
   	int i;
   	for(i=1;i<=n;i++)
   	printf("%d %d %d\n",stack[i].x-1,stack[i].y-1,stack[i].choose);
   } 
   
   int main(){
   	freopen("codevs1136.in","r",stdin);
   	freopen("codevs1136.out","w",stdout);
   	work();
   	fclose(stdin);
   	fclose(stdout);
   	return 0;
   }
   

    

2. codevs1064 虫食算

   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #define L_L "%I64d"
   #define N 28
   using namespace std;
   int use[N],val[N];
   int a[N][3];
   int n;
   int chs[N];
   bool flag=false;
   inline bool check(int i){
   	int u,v;
   	for(i--;i;i--){
   			if(chs[a[i][0]]&&chs[a[i][1]]&&chs[a[i][2]]){
   	    		v=(val[a[i][0]]+val[a[i][1]])%n;
   	    		if(v!=val[a[i][2]]&&(v+1)%n!=val[a[i][2]]){
   	    			//printf("false %d %d %d %d %d\n",i,val[a[i][0]],val[a[i][1]],val[a[i][2]],(val[a[i][0]]+val[a[i][1]]+1)%n);
   	    			return false;
   				}
   			}
   	}
   	return true;
   }
   inline void DFS(int now,int jin){
   	
   	int u,v,w,i,j; 
   
   	if(now==0){
   		if(jin)return;
   		flag=true;
   		return;
   	}
   	if(chs[a[now][0]]&&chs[a[now][1]]&&chs[a[now][2]]){
   		if((jin+val[a[now][0]]+val[a[now][1]])%n==val[a[now][2]]){
   			jin=(jin+val[a[now][0]]+val[a[now][1]])/n;
   			DFS(now-1,jin);
   	   }
   	   return;
   	}//¶¼ÓÐ
   	
   	if(chs[a[now][0]]&&chs[a[now][1]]){
   		
   	   v=(jin+val[a[now][0]]+val[a[now][1]])%n;
   	  // printf("caseV %d %d %d %d %d[%d %d %d]%d\n",now,v,jin,val[a[now][0]],val[a[now][1]],a[now][0],a[now][1],a[now][2],use[v]);
   	   if(use[v])return;//false
   	 //  printf("yes %d\n",v);
   	   jin=(jin+val[a[now][0]]+val[a[now][1]])/n;
   	   chs[a[now][2]]=1;val[a[now][2]]=v;use[v]=1;
   	  // printf("beginer%d\n",v);
   	    if(!check(now)){//printf("false %d\n",v);
   	    	chs[a[now][2]]=0;val[a[now][2]]=0;use[v]=0;
   		return; 
   		}
   		DFS(now-1,jin);
   		if(!flag){
   			chs[a[now][2]]=0;val[a[now][2]]=0;use[v]=0;
   		}
   		return;
   	}
   	if(chs[a[now][2]]&&(chs[a[now][1]]||chs[a[now][0]])){
   		u=chs[a[now][0]]?1:0;
   		v=(val[a[now][2]]-val[a[now][u^1]]-jin)%n;
   		if(v<0)v+=n;
   		if(use[v])return;
   		chs[a[now][u]]=1;val[a[now][u]]=v;use[v]=1;
   		jin=(jin+val[a[now][0]]+val[a[now][1]])/n;
   		
   		//	printf("caseF %d %d %d %d %d[%d %d %d]%d %d\n",now,u,jin,val[a[now][0]],val[a[now][1]],a[now][0],a[now][1],a[now][2]);
   	
   		if(!check(now)) {
   			chs[a[now][u]]=0;val[a[now][u]]=0;use[v]=0;
   		return;
   		}
   		DFS(now-1,jin);
   		if(!flag){
   		chs[a[now][u]]=0;val[a[now][u]]=0;use[v]=0;
   		} 
   		return;
   	} 
   	//ÓÐÁ½¸ö
   	if(chs[a[now][0]]||chs[a[now][1]]){
   		u=chs[a[now][0]]?1:0;
   	  // 	if(val[a[12][0]]==8&&val[a[12][1]]==5&&val[a[12][2]]==1)
   	//printf("DFS %d\n",now);
   		for(i=0;i'Z')
   		ch=getchar();
   		a[j][i]=ch-'A'+1;
   	}
   	}
   	DFS(n,0);
   	for(i=1;i<=n;i++)
   	printf("%d ",val[i]);
   }
   int main(){
   	freopen("codevs1064.in","r",stdin);
   	freopen("codevs1064.out","w",stdout);
   	work();
   	fclose(stdin);
   	fclose(stdout);
   	return 0;
   }
   

    

3. codevs4610 斗地主

   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #include
   #define L_L "%I64d"
   #define N 20
   using namespace std;
   int t,n;
   int a[N];
   int ans;
   int b[5];
   inline void dfs2(int b1,int b2,int b3,int b4,int nt,int jie,int r1,int r2,int yes){
   	//yes±íʾÊÇ·ñÓÐ3¸ö´ø1¸ö£¬Õâ¿ÉÒÔ½â¾ö1¸öÂäµ¥ÊÇ·ñ¿ÉÒÔ±»´øµÄÇé¿ö£¨Ëĸö²»ÄÜ´øµ¥ÅÆ£©
   	if(nt>=ans)return;
   	//×îÖØÒªµÄÊǼÆËã 
   	if(b3==0&&b4==0){
   		//printf("calc %d %d %d %d %d\n",b1,b2,b3,b4,nt);
   		if((b1&1)&&!yes&&r1){
   			//ÖÁÉÙÒª¶à´òÒ»Õŵ¥ÅÆ
   			if(b2<=r2){
   				b2=0;r2=0;
   				if(r1>b1)
   				nt++;
   				else {
   					nt+=(b1-r1);
   				}
   				if(ans>nt)ans=nt;
   				return;
   			} 
   			else if(r1<=b1){
   			    {
   			    	nt=nt+(b1-r1)+(b2-r2);
   			    	if(ans>nt)ans=nt;
   			    	return;
   				}
   			}else {
   				//b1<=r1,b2>=r2
   				r1-=(b1-1);nt++;
   				b2-=(r1>>1);
   				b2-=r2;
   				if(b2<0)b2=0;
   				nt+=b2;
   				if(ans>nt)ans=nt;
   				return;
   			} 
   		}
   		else {//printf("case2\n");
   			if(b2<=r2){
   				b2=0;r2=0;
   				if(r1>=b1);
   				else {
   					nt+=(b1-r1);
   				}
   				if(ans>nt)ans=nt;
   				return;
   			}
   			else if(r1<=b1)//r2<=b2
   			{//printf("oh %d\n",nt+b1-r1+b2-r2);
   				nt=nt+(b1-r1)+(b2-r2);
   				if(ans>nt)ans=nt;
   				return; 
   			}
   			else {//b1<=r1,b2>=r2
   				r1-=b1;
   				b2-=(r1>>1);
   				b2-=r2;
   				if(b2<0)b2=0;
   				nt+=b2;
   				if(ans>nt)ans=nt;
   				return;
   			}
   		}
   	}
   	//¼ÆËãÍêÖ®ºó¾Í¼òµ¥Ã¶¾ÙÁË
   	if(b4){
   		if(jie<=0)
   			dfs2(b1,b2,b3,b4-1,nt+1,0,r1,r2+2,0);
   		if(jie<=1)	
   			dfs2(b1,b2,b3,b4-1,nt+1,1,r1+2,r2,0);
   		if(jie<=2)	
   			dfs2(b1,b2,b3,b4-1,nt+1,2,r1,r2,0);
   		if(jie<=3)	
   			dfs2(b1,b2+2,b3,b4-1,nt,3,r1,r2,0);
   		if(jie<=4)	
   			dfs2(b1+b4,b2,b3+b4,0,nt,4,r1,r2,0);
   	}
   	else if(b3){
   		if(jie<=4)
   		   dfs2(b1,b2,b3-1,0,nt+1,4,r1,r2+1,0);
   		 if(jie<=5)
   		   dfs2(b1,b2,b3-1,0,nt+1,5,r1+1,r2,0);
   		 dfs2(b1+1,b2+1,b3-1,0,nt,5,r1,r2,0);
   	} 
   }
   void solve(int nt){
   	//¹íÖ±½Óö¾Ù£¬ËùÓÐÅƼÆÊý¼´¿É
   	int i;
   	b[1]=b[2]=b[3]=b[4]=0;
   	for(i=0;i<=15;i++)
   	if(a[i])
   	b[a[i]]++;
   	//printf("solve %d %d %d %d ;%d %d; %d\n",b[1],b[2],b[3],b[4],a[16],a[17],nt);
   	if(a[16]&&a[17]){
   		dfs2(b[1],b[2],b[3],b[4],nt+1,0,0,0,0);//Ë«¹í 
   	}
   	dfs2(b[1]+a[16]+a[17],b[2],b[3],b[4],nt,0,0,0,0);//µ¥´ò 
   }
   inline void dfs(int now,int nt){
   	//¾¡Á¿Ì°ÐijöÅÆ£¬±ãÓÚ¿ìËٱƽü½ÏÓŽâ 
   	if(nt>=ans)return;
   	if(now==15){
   		solve(nt);return;
   	}
   	int i;
   	for(i=0;i+now<=14;i++)
   	if(a[i+now]<3)
   	{
   		break;
   	}
   	else a[i+now]-=3;
   	for(i--;i>=1;i--){
   		dfs(now,nt+1);
   		a[i+now]+=3;
   	}
   	for(;i>=0;i--)
   	a[i+now]+=3;
   	for(i=0;i+now<=14;i++)
   	if(a[i+now]<2){
   		break;
   	}
   	else a[i+now]-=2;
   	for(i--;i>=2;i--){
   		dfs(now,nt+1);
   		a[i+now]+=2;
   	}
   	for(;i>=0;i--)
   	a[i+now]+=2;
   	for(i=0;i+now<=14;i++)
   	if(!a[i+now]){
   	break;
   	}else a[i+now]--;
   	for(i--;i>=4;i--)
   	{
   		dfs(now,nt+1);
   		a[i+now]++;
   	}
   	for(;i>=0;i--)
   	a[i+now]++;
   	dfs(now+1,nt);
   }
   void work(){
   	scanf("%d%d",&t,&n);
   	while(t--){
   		memset(a,0,sizeof(a));
   		int u,v,i;
   		for(i=1;i<=n;i++){
   			scanf("%d%d",&u,&v);
   			if(u==2||u==1)
   			u+=13;
   			else if(u==0&&v==1)
   			u=16;
   			else if(u==0&&v==2)
   			u=17;
   		//	printf("u=%d v=%d\n",u,v);
   			a[u]++;
   		}
   		ans=n;
   	//	for(i=3;i<=17;i++)
   	//	printf("%d ",a[i]);
   	//	printf("\n");
   		dfs(3,0);
   		printf("%d\n",ans);
   	}
   	
   }
   int main(){
   	freopen("codevs4610.in","r",stdin);
   	freopen("codevs4610.out","w",stdout);
   	work();
   	fclose(stdin);
   	fclose(stdout);
   	return 0;
   }