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 10
4
), 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
题目大意：给出一个无向图，并给出每个顶点所对应的颜色，若每个边所对应的两个顶点颜色都不相同，则满足题意
思路分析：用vector把所有的边都存起来，把所有的顶点的颜色用set存储起来（利用set自动去重），枚举所有边，检查是否每条边的两个顶点的颜色不同，若都不同则输出颜色个数，否则输出No
#include <iostream>
#include <stdio.h>
#include <vector>
#include <set>
using namespace std;
struct edge{
int n1;
int n2;
};
int main()
{
int n,m,k;
scanf("%d %d",&n,&m);
vector<edge> v(m);
for(int i = 0; i < m; i++ )
scanf("%d %d",&v[i].n1,&v[i].n2);
scanf("%d",&k);
while(k--){
int NodeColor[10009]; //注意需要放在while循环内，每次都需要重新利用
set<int> color;
for(int i = 0; i < n; i++){
scanf("%d",&NodeColor[i]);
color.insert(NodeColor[i]);
}
bool flag = true;
for(int i = 0; i < m; i++){
if(NodeColor[v[i].n1] == NodeColor[v[i].n2]){
flag = false;
break;
}
}
if(flag)
printf("%d%s\n",color.size(),"-coloring");
else
printf("No\n");
}
return 0;
}