数组中最大子数组之和

题目

[1, -2, 3, 5, -3, 2] 返回：8
[0, -2, 3, 5, -1, 2] 返回：9
[-9, -2, -3, -5, -3] 返回：-2

主要程序

int MaxSum4(int *A, int n,int &beg,int &end)

{

    if(A==NULL||n<=1)

    {

        cout<<"error input"<<'\n';

        exit(0);

    }

    if(n==1)

        return A[0];

    int pos = 0;

    int CurSum = A[0];

    int MaxSum = A[0];

    for(int i = 1; i<n;++i)

    {

        if(CurSum<=0)

            CurSum = 0;

        CurSum += A[i];

        if(CurSum>=MaxSum)

        {

            MaxSum = CurSum;

            pos = i;

        }

    }

    int pos1 = 0,max1 = A[0];

    CurSum = A[0]; 

    for(int i = 1;i<=n-1;++i)

    {

        CurSum += A[i];

        if(CurSum>=max1)

        {

            max1 = CurSum;

            pos1 = i;

        }

    }

    CurSum = A[n-1];

    int pos2 = n-1, max2 = A[n-1];

    for(int j = n-2; j>=0; --j)

    {

        CurSum += A[j];

        if(CurSum>=max2)

        {

            max2 = CurSum;

            pos2 = j;

        }

    }

    int sum = 0;

    if(pos1>=pos2)

    {

        for(int i = 0; i<n; ++i)

            sum+=A[i];

    }

    else

    {

        for(int i = 0; i<=pos1; ++i)

        {

            sum+=A[i];

        }

        for(int j = n-1; j>=pos2; --j)

        {

            sum+=A[j];

        }

    }

    int temp = MaxSum>sum?MaxSum:sum;

    if(MaxSum==temp)

    {

        end = pos;

        while(temp!=0)

        {

            temp-=A[pos--];

        }

        beg = ++pos;

        return MaxSum;

    }

    else

    {

        if(pos1>=pos2)

        {

            beg = 0;

            end = n-1;

        }

        else

        {

            end = pos2;

            beg = pos1;

        }

        return sum;

    }

    return MaxSum>sum?MaxSum:sum;

}

转载于:https://www.cnblogs.com/zhaocen/p/6644447.html