[HDU 5113] Black And White (dfs+剪枝)

 1 #include <cstdio>
 2 #include <algorithm>
 3 #include <cstring>
 4 #include <vector>
 5 using namespace std;
 6 typedef long long LL;
 7 typedef pair<int,int> PII;
 8 typedef vector<int> vec;
 9 typedef vector<vec> mat;
10 #define AA first
11 #define BB second
12 
13 int T,N,M,K;
14 int m[10][10];
15 int c[100];
16 bool hasAns;
17 
18 bool C(int x,int y,int c){
19     int row = true, column = true;
20     if( x-1>=1&&m[x-1][y]==c ) column = false;
21     if( y-1>=1 && m[x][y-1]==c ) row = false;
22     return row&&column;
23 }
24 
25 void dfs(int x,int y,int cur){
26     for(int i=1;i<=K;i++){
27         if( c[i]>(cur+1)/2 ) return;
28     }
29     if(hasAns) return;
30     if( x==N+1 ){
31         hasAns = true;
32         puts("YES");
33         for(int i=1;i<=N;i++) {
34             for(int j=1;j<=M;j++ ){
35                 printf(j==M?"%d\n":"%d ",m[i][j]);
36             }
37         }
38         return;
39     }
40     for(int i=1;i<=K;i++)if( c[i] ){
41         if( C(x,y,i) ){
42             c[i]--;
43             m[x][y] = i;
44             if( y==M ) dfs(x+1,1,cur-1);
45             else dfs(x,y+1,cur-1);
46             c[i]++;
47             m[x][y] = 0;
48         }
49     }
50 }
51 
52 int main(){
53     scanf("%d",&T);
54     for(int cases = 1; cases <= T; cases++){
55         scanf("%d%d%d",&N,&M,&K);
56         for(int i=1;i<=K;i++){
57             scanf("%d",&c[i]);
58         }
59         hasAns = false;
60         printf("Case #%d:\n",cases);
61         dfs(1,1,N*M);
62         if(!hasAns) puts("NO");
63     }
64     return 0;
65 }