差分数组

 

 差分数组的适用场景是：频繁对原始数组的某个区间的元素进⾏增减。

?

1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34

//第一步：构建差分数组 func Diff(nums []int)[]int{     m:=len(nums)     if m==0{         return []int{}     }     diff:=make([]int,m)     diff[0]=nums[0]     for i:=1;i<m;i++{         diff[i]=nums[i]-nums[i-1]     }     return diff }   //第二步：给闭区间[i,j]增加val func Increment(diff []int,i ,j, val int){     diff[i]+=val     if j+1<len(diff){         diff[j+1]-=val     } }   //第三步：返回结果数组 func Result(diff []int)[]int{     if len(diff)==0{         return []int{}     }     res:=make([]int,len(diff))     res[0]=diff[0]     for i:=1;i<len(diff);i++{         res[i]=res[i-1]+diff[i]     }     return res }