【算法题】- 求和等于K子数组

一整数（有正有负）数组，用尽量少的时间计算数组中和为某个整数的所有子数组

public class SumK {

    public static void main(String[] args) {
        
        int[] array = {4,5,2,4,7,1,8,-3,6,3,2,6,1,4,-6,7,-4,2,-1,8,5,2,7,4,3};
        int k = 11;
        Map<Integer,Integer> set = new HashMap<Integer,Integer>();
        int[] sum = new int[array.length];
        sum[0]=array[0];
        set.put(sum[0], 0);
        for(int i =1 ; i < array.length ;i++){
            sum[i]=sum[i-1]+array[i];
            set.put(sum[i],i);
        }
        int count = 1;
        for(int i=array.length-1;i>0;i--){
            int key = sum[i]-k;
            if(set.get(key) != null && set.get(key) != 0){
                System.out.print("第"+count+++"组字串 ");
                for(int j = set.get(key)+1 ; j <=i ;j++){
                    System.out.print(array[j]+" ");
                }
                System.out.println();
            }
        }
    }
}

思路是把子数组的和转化成前缀数组之间的差等于K，然后从后遍历。