ZOJ 1084 贪心 给顶点染色，相邻顶点不能染同样的颜色 算法有问题不能保证是最优解但能A
贴代码：
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1 #include <cstdio> 2 #include <cstring> 3 #define MAXN 30 4 int n; 5 bool edge[MAXN][MAXN]; 6 int color() 7 { 8 int vet[MAXN]; 9 int c[MAXN]; 10 int i,j; 11 memset(vet,0xff,sizeof(vet)); 12 for( i=0; i<n; ++i) 13 { 14 memset(c,0,sizeof(c)); 15 for( j=0; j<n; ++j) 16 { 17 if(edge[i][j] && vet[j] != -1) 18 c[vet[j]] = 1; 19 } 20 for(j=0; j<n; ++j) 21 if(!c[j]) break; 22 vet[i] = j; 23 } 24 int max = -1; 25 for(int i=0; i<n; ++i) 26 if(vet[i] > max) max = vet[i]; 27 return max+1; 28 } 29 int main() 30 { 31 freopen("in.cpp","r",stdin); 32 while(~scanf("%d",&n)) 33 { 34 if(n==0) break; 35 memset(edge,0,sizeof(edge)); 36 char a[34]; 37 for(int i=0; i<n; ++i) 38 { 39 scanf("%s",a); 40 int len=strlen(a); 41 int u = a[0]-'A'; 42 for(int j=2; j<len; ++j) 43 { 44 int v = a[j]-'A'; 45 edge[u][v] = edge[v][u] = 1; 46 } 47 } 48 int p = color(); 49 if(p == 1) 50 printf("%d channel",p); 51 else 52 printf("%d channels",p); 53 printf(" needed.\n"); 54 } 55 return 0; 56 }
