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
注意：set容器能共自动过滤掉相同的元素
题目大意：
编号0-n-1的n个节点分别染上一种颜色，问是否满足同一条边的两个节点不同色.
分析：先将所有的边存下，在将所有节点的颜色存下（用set存颜色同时可以判断有多少种不同的颜色）。然后判断每条边的两个节点是否同色。
#include<iostream>
#include<set>
#include<stdio.h>
#pragma warning(disable:4996)
using namespace std;
int n, m, k;
struct Node
{
int l, r;
}e[10004];
int a[10002];
set<int>c;
int main()
{
cin >> n >> m;
for (int i = 0; i < m; i++)
cin >> e[i].l >> e[i].r;
cin >> k;
while (k--)
{
c.clear();
int flag = true;
for (int i = 0; i < n; i++) {
cin >> a[i];
c.insert(a[i]);
}
for (int i = 0; i < m; i++) {
if (a[e[i].l] == a[e[i].r]) {
flag = false; break;
}
}
if (flag) {
printf("%d-coloring
", c.size());
}
else {
printf("No
");
}
}
return 0;
}