PAT_A1154#Vertex Coloring

Source:

PAT A 1154 Vertex Coloring (25 分)

Description:

A proper vertex coloring is a labeling of the graph's vertices with colors such that no two vertices sharing the same edge have the same color. A coloring using at most k colors is called a (proper) k-coloring.

Now you are supposed to tell if a given coloring is a proper k-coloring.

Input Specification:

Each input file contains one test case. For each case, the first line gives two positive integers N and M(both no more than 1), being the total numbers of vertices and edges, respectively. Then M lines follow, each describes an edge by giving the indices (from 0 to N−1) of the two ends of the edge.

After the graph, a positive integer K (≤ 100) is given, which is the number of colorings you are supposed to check. Then K lines follow, each contains N colors which are represented by non-negative integers in the range of int. The i-th color is the color of the i-th vertex.

Output Specification:

For each coloring, print in a line k-coloring if it is a proper k-coloring for some positive k, or No if not.

Sample Input:

10 11
8 7
6 8
4 5
8 4
8 1
1 2
1 4
9 8
9 1
1 0
2 4
4
0 1 0 1 4 1 0 1 3 0
0 1 0 1 4 1 0 1 0 0
8 1 0 1 4 1 0 5 3 0
1 2 3 4 5 6 7 8 8 9

Sample Output:

4-coloring
No
6-coloring
No

Keys:

• 图的存储和遍历
• set（C++ STL）
• 散列（Hash）

Attenrion:

• 矩阵存储图，规模小于10^3
• 对于多组测试用例的输入，要注意统计值和哈希函数的初始化（出题老师太坏了，测试用例即使不初始化也是对的-,-）

Code:

 /*
 Data: 2019-08-02 21:08:29
 Problem: PAT_A1154#Vertex Coloring
 AC: 17:39

 题目大意：
 判断图中相连的顶点是否共色
 */
 #include<cstdio>
 #include<set>
 using namespace std;
 const int M=1e4+;
 struct node
 {
     int u,v;
 }grap[M];
 int color[M];

 int main()
 {
 #ifdef ONLINE_JUDGE
 #else
     freopen("Test.txt", "r", stdin);
 #endif // ONLINE_JUDGE

     int n,m,k;
     scanf("%d%d", &m,&n);
     for(int i=; i<n; i++)
         scanf("%d%d", &grap[i].u,&grap[i].v);
     scanf("%d", &k);
     while(k--)
     {
         set<int> mp;
         for(int i=; i<m; i++)
         {
             scanf("%d", &color[i]);
             mp.insert(color[i]);
         }
         for(int i=; i<n; i++)
         {
             if(color[grap[i].u] == color[grap[i].v])
             {
                 mp.clear();
                 break;
             }
         }
         if(mp.size())
             printf("%d-coloring\n", mp.size());
         else
             printf("No\n");
     }

     return ;
 }