算法总结之 未排序数组中累加和小于或等于给定值的最长子数组长度

package TT;

public class Test72 {
  
     public static int maxLength(int[] arr, int k ){
         
         int[] h = new int[arr.length+1];
         
         int sum = 0;
         h[0] = sum;
         
         for(int i =0; i !=arr.length; i++){
             sum +=arr[i];
             h[i+1]=Math.max(sum, h[i]);
         }
         
         sum = 0;
         int res = 0;
         int pre = 0;
         int len = 0;
         
         for(int i =0; i!=arr.length; i++){
             
             sum +=arr[i];
             pre = getLessIndex(h, sum-k);
             len = pre == -1 ? 0 : i-pre+1;
             res = Math.max(res, len);
     
         } 
         return res;          
     }
    
     public static int getLessIndex(int[] arr, int num){
         int low = 0;
         int high = arr.length-1;
         int mid = 0;
         int res=-1;
         while(low <= high){
             mid = (low+high)/2;
             if(arr[mid]>=num){
                 res=mid;
                 high=mid-1;
             }else {
                low = mid +1;
            }     
         }
           
         return res;     
     }
    
     public static void main(String[] args){
         
          int[] arr = new int[5];
          arr[0]=3;
          arr[1]=-2;
          arr[2]=-4;
          arr[3]=0;
          arr[4]=6;

        int x = maxLength(arr,-2);
        System.out.println(x);
          
         
         
     }
     
     
     
}