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对于最优化的子数组问题，一名话，就是从给你的数组中寻找一个子数组，使得它的和是最优的（最大/最小）如果数组中元素全是正的，那么好办，整个数组的和就是了。如果数组中元素全是负的，那么也好办，找最小的那个。但是如果正负相间呢？？？
#include<iostream>#define MIN -255;struct returnVal{int left;int right;int sum;};struct returnVal*findMaxCrossingSubarray(int left,int mid ,int right,int *arr);struct returnVal *findMaxSubarray(int left,int right ,int *arr);struct returnVal*findMaxCrossingSubarray(int left,int mid ,int right,int *arr){int leftMaxSum=MIN;int sum=0;int maxLeft=0;int i,j;for(i=mid ; i>=left; i--){sum+=arr[i];if(sum>leftMaxSum){leftMaxSum=sum;maxLeft=i;}}sum=0;int rightMaxSum=MIN;int maxRight=0;for(int j=mid+1; j<=right; j++){sum+=arr[j];if(sum>rightMaxSum){rightMaxSum=sum;maxRight=j;}}struct returnVal *val=new returnVal;val->left=maxLeft;val->right=maxRight;val->sum=rightMaxSum+leftMaxSum;return val;}inline struct returnVal* maxThree_returnVal(struct returnVal *left,struct returnVal *mid,struct returnVal *right){if(left->sum>=mid->sum&&left->sum>=right->sum){return left;}if(right->right>=left->sum&&right->sum>=mid->sum){return right;}if(mid->sum>=left->sum&&mid->sum>=right->sum){return mid;}}struct returnVal *findMaxSubarray(int left,int right ,int *arr){if(left==right){struct returnVal *val=new returnVal;val->left=left;val->right=right;val->sum=arr[left];return val;}struct returnVal *valRight;struct returnVal *valCross;struct returnVal *valLeft;int mid=(left+right)/2;valLeft=findMaxSubarray(left,mid,arr);valRight=findMaxSubarray(mid+1,right,arr);valCross=findMaxCrossingSubarray(left,mid,right,arr);return maxThree_returnVal(valLeft,valCross,valRight);}
int arr[16]={13,-3,-25,20,-3,-16,-23,18,20,-7,12,-5,-22,15,-4,7};int main(){struct returnVal *val=new returnVal;val=findMaxSubarray(0,15,arr);std::cout<<val->left<<","<<val->right<<","<<val->sum<<std::endl;}
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原文地址：http://www.cnblogs.com/yml435/p/4655522.html
