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//分治算法研究
var cc=console
function find_max_crossing_subarray(A,low,mid,high){
var max_left=mid,max_right=mid
var left_sum=0
var sum=0
for(var i=mid;i>=low;i--){
sum=sum+A[i]
if(sum>left_sum){
left_sum=sum
max_left=i
}
}
var right_sum=0
var sum=0
for(var i=mid+1;i<=high;i++){
sum=sum+A[i]
if(sum>right_sum){
right_sum=sum
max_right=i
}
}
return [max_left,max_right,left_sum+right_sum]
}
//搜索跨越中点的最大连续子集和
var arr=[13,-3,-2,20,-3,-16,-23,18,20,-7,12,-5,-22,15,-4,7]
//var re=find_max_crossing_subarray(arr,0,8,arr.length-1)
//cc.log(re)//=>18,20,-7,12
function find_maximum_subarray(A,low,high){
if(high==low){
return [low,high,A[low]]
}else{
var mid=(low+high)>>1
/*[left_low,left_high,left_sum]*/
var left=find_maximum_subarray(A,low,mid)
/*[right_low,right_high,right_sum]*/
var right=find_maximum_subarray(A,mid+1,high)
/*[cross_low,cross_high,cross_sum]*/
var cross=find_max_crossing_subarray(A,low,mid,high)
if(left[2]>=right[2]&&left[2]>=cross[2]){
return left
}else if(right[2]>=left[2]&&right[2]>=cross[2]){
return right
}else if(cross[2]>=left[2]&&cross[2]>=right[2]){
return cross
}
}
}
//搜索数组中的最大连续 子集和
var re2=find_maximum_subarray(arr,0,arr.length-1)
cc.log(re2)//=>18,20,-7,12 [7,10,42]
2.分治算法研究-搜索数组中的最大连续子集和 2014-3-11 11:37 阅读(16)
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原文地址：http://www.cnblogs.com/caoke/p/4389740.html
