分治法之求最大连续子序列和

对原问题有如下解
1.最大子序列在数组中点的左边
2.最大子序列在数组中点的右边
3.最大子序列跨越数组中点

#include
using namespace std;
int FIND_MAX_CROSSING_SUBARRAY(int a[],int low,int high)
{
    int mid = (low+high)/2;
    int i = mid;
    int j = mid+1;
    int left_sum = 0;
    int right_sum = 0;
    int sum = 0;
    while(i>=low){
        sum += a[i];
        if(sum>left_sum)    left_sum = sum;
        i--;
    }
    sum = 0;
    while(j<=high){
        sum += a[j];
        if(sum>right_sum)   right_sum = sum;
        j++;
    }
    return left_sum+right_sum;
}

int FIND_MAXIMUM_SUBARRAY(int a[],int low, int high)
{
    if(low == high)     return a[low];
    int mid = (low+high)/2;
    int left_sum = FIND_MAXIMUM_SUBARRAY(a,low,mid);
    int right_sum = FIND_MAXIMUM_SUBARRAY(a,mid+1,high);
    int cross_sum = FIND_MAX_CROSSING_SUBARRAY(a,low,high);
    if(cross_sum>left_sum && cross_sum>right_sum)   return cross_sum;
    if(left_sum>cross_sum && left_sum>right_sum)    return left_sum;
    if(right_sum>left_sum && right_sum>cross_sum)   return right_sum;
}
int main() 
{
    int a[10] = {-1,0,23,414,-231,11,4234,-131323,1321,321};
    cout<0,9);
}