Black And White
Time Limit: 2000/2000 MS (Java/Others) Memory Limit: 512000/512000 K (Java/Others)
Total Submission(s): 527 Accepted Submission(s): 145
Special Judge
Problem Description
In mathematics, the four color theorem, or the four color map theorem, states that, given any separation of a plane into contiguous regions, producing a figure called a map, no more than four colors are required to color the regions of the map so that no two adjacent regions have the same color.
— Wikipedia, the free encyclopedia
In this problem, you have to solve the 4-color problem. Hey, I’m just joking.
You are asked to solve a similar problem:
Color an N × M chessboard with K colors numbered from 1 to K such that no two adjacent cells have the same color (two cells are adjacent if they share an edge). The i-th color should be used in exactly ci cells.
Matt hopes you can tell him a possible coloring.
Input
The first line contains only one integer T (1 ≤ T ≤ 5000), which indicates the number of test cases.
For each test case, the first line contains three integers: N, M, K (0 < N, M ≤ 5, 0 < K ≤ N × M ).
The second line contains K integers ci (ci > 0), denoting the number of cells where the i-th color should be used.
It’s guaranteed that c1 + c2 + · · · + cK = N × M .
Output
For each test case, the first line contains “Case #x:”, where x is the case number (starting from 1).
In the second line, output “NO” if there is no coloring satisfying the requirements. Otherwise, output “YES” in one line. Each of the following N lines contains M numbers seperated by single whitespace, denoting the color of the cells.
If there are multiple solutions, output any of them.
Sample Input
4
1 5 2
4 1
3 3 4
1 2 2 4
2 3 3
2 2 2
3 2 3
2 2 2
Sample Output
Case #1:
NO
Case #2:
YES
4 3 4
2 1 2
4 3 4
Case #3:
YES
1 2 3
2 3 1
Case #4:
YES
1 2
2 3
3 1
·学习傅总思路打出来的代码,基本相同。
http://fudq.blog.163.com/blog/static/191350238201411271332692/
·一直还是比较怕dfs的,我只能说,,,练吧。。。。
·这题的剪枝也是醉了,现场想到了,加的位置不对还是没过,,,不知道是否是出题者故意的,,如果是就太神了。。
AC Code:
1 #include <iostream> 2 #include <stdio.h> 3 #include <algorithm> 4 #include <cstring> 5 #include <string.h> 6 #include <math.h> 7 #include <queue> 8 #include <stack> 9 #include <stdlib.h> 10 #include <map> 11 using namespace std; 12 #define LL long long 13 #define sf(a) scanf("%d",&(a)); 14 15 #define N 21 16 int r[N][N]; 17 int n,m,flag,k; 18 int f[10010]; 19 //染色: dfs,深搜 + 剪枝 20 21 22 void Output(){ 23 printf("YES\n"); 24 for(int i=1;i<=n;i++){ 25 //if(i==0) printf("%d",r[i][0]); 26 for(int j=1;j<=m;j++) 27 if(j==1) 28 printf("%d",r[i][j]+1); 29 else printf(" %d",r[i][j]+1); 30 printf("\n"); 31 } 32 } 33 int jud(int x,int y,int i){ 34 if(r[x-1][y] == i) return 0; 35 if(r[x][y-1] == i) return 0; //表示此种方式不行! 36 return 1; 37 } 38 void dfs(int x,int y,int cnt){ 39 if(flag) return ; 40 if(cnt == 0){ 41 flag=1; 42 Output(); 43 return ; 44 } 45 //加上剪枝 46 for(int i=0;i<k;i++){ 47 if(f[i] > (cnt+1)/2) return ; //直接返回,此时不成功! 48 } 49 for(int i=0;i<k;i++){ 50 if(f[i] && jud(x,y,i)){ 51 r[x][y] = i; 52 f[i]--; 53 if(y==m) dfs(x+1,1,cnt-1); 54 else dfs(x,y+1,cnt-1); 55 r[x][y]=-1; 56 f[i]++; 57 } 58 } 59 60 } 61 int main(){ 62 int T,cas=1; 63 scanf("%d",&T); 64 while(T--){ 65 printf("Case #%d:\n",cas++); 66 scanf("%d %d %d",&n,&m,&k); 67 flag=0; 68 for(int i=0;i<k;i++) scanf("%d",&f[i]); 69 memset(r,-1,sizeof(r)); 70 dfs(1,1,n*m); 71 if(!flag) printf("NO\n"); 72 } 73 74 return 0; 75 }