求数组中和为给定数的所有组合详解编程语言

import java.util.Arrays; 
 
public class Test {
    
	public static void main(String[] args) {
    
		String str = "6,2,7,3,8,1,9,4"; 
		double sum = 12; 
		diguiSum(str, sum); 
	} 
 
	public static void diguiSum(String str, double sum) {
    
		String[] x = str.split(","); 
		double[] array = arrayTransform(x); 
		for (int i = 0; i < 100; i++) {
    
			double[] cache = new double[i + 1]; 
			int ceng = -1; 
			int cengQuit = i; 
			int startPiont = 0; 
			cir(ceng, cengQuit, startPiont, array, cache, sum); 
		} 
	} 
 
	// 递归求结果 
	public static void cir(int ceng, int cengQuit, int startPiont, 
			double[] array, double[] cache, double sum) {
    
		ceng++; 
		for (int i = startPiont; i < array.length; i++) {
    
			cache[ceng] = array[i]; 
			if (ceng == cengQuit) {
    
				if (getSum(cache) == sum) {
    
					printcache(cache); 
				} 
				if (getSum(cache) > sum) {
    
					break; 
				} 
			} 
			if (ceng < cengQuit) {
    
				startPiont = i + 1; 
				cir(ceng, cengQuit, startPiont, array, cache, sum); 
			} 
		} 
	} 
 
	// 获取组合数字之和 
	public static double getSum(double[] cache) {
    
		double sum = 0; 
		for (int i = 0; i < cache.length; i++) {
    
			sum = sum + cache[i]; 
		} 
		return sum; 
	} 
 
	// 打印组合的可能 
	public static void printcache(double[] cache) {
    
		for (int i = 0; i < cache.length; i++) {
    
			System.out.print(cache[i] + ","); 
		} 
		System.out.println(); 
	} 
 
	// 转换数组类型 且为提高效率做准备 
	public static double[] arrayTransform(String[] strArray) {
    
		int length = 0; 
 
		double[] array = new double[strArray.length]; 
		for (int i = 0; i < strArray.length; i++) {
    
			array[i] = Double.valueOf(strArray[i]); 
		} 
		Arrays.sort(array); 
		for (int i = 0; i < array.length; i++) {
    
			if (array[i] > 100) {
    
				length = i; 
				break; 
			} 
		} 
		double[] dest = new double[length]; 
		if (length == 0) {
    
			return array; 
		} 
		System.arraycopy(array, 0, dest, 0, length); 
		return dest; 
	} 
} 

输出结果为：

3.0,9.0, 
4.0,8.0, 
1.0,2.0,9.0, 
1.0,3.0,8.0, 
1.0,4.0,7.0, 
2.0,3.0,7.0, 
2.0,4.0,6.0, 
1.0,2.0,3.0,6.0,