以三色问题为例：
运行结果：
对给定无向图着色，相邻点颜色不能相同，限用3种颜色
在框架基础上的实现：
import java. util.Vector ;
public class ThreeColor extends CombineProblem {
int[][] graph;
int start ;
public ThreeColor (int[][] graph, int start) {
super();
this.graph = graph;
this.start = start;
this.flag = false ;
this.n = graph. length;
this.x = new Integer[n];
}
@Override
public Vector <Comparable> makeItem(int k) {
Vector <Comparable> vec = new Vector<Comparable>();
for ( int i = 1 ; i <= 3 ; i++) {
vec .add( i);
}
return vec;
}
@Override
public boolean complete (int k) {
return k >= n;
}
@Override
public void printSolution (int k) {
for ( int i = 0 ; i < x.length; i ++) {
System .out. print(x [i] + " ");
}
System .out. println();
}
@Override
public boolean isPartial (int k) {
for ( int i = 0 ; i < k; i++) {
if ( graph[k ][i] == 1 && x [k] == x[i ]) {
return false ;
}
}
return true ;
}
}
主函数：
public class Main {
public static void main (String[] args) {
int[][] graph = { { 0, 1 , 1 , 0 }, { 1, 0, 0, 1 }, { 1 , 0 , 0 , 1 },
{ 0 , 1 , 1 , 0 } };
Problem p = new ThreeColor(graph , 0 );
p .explore(0);
if (! p.flag) {
System .out. println("no solution!" );
}
}
}
1 2 2 1
1 2 2 3
1 2 3 1
1 3 2 1
1 3 3 1
1 3 3 2
2 1 1 2
2 1 1 3
2 1 3 2
2 3 1 2
2 3 3 1
2 3 3 2
3 1 1 2
3 1 1 3
3 1 2 3
3 2 1 3
3 2 2 1
3 2 2 3