3664=顺序表应用7：最大子段和之分治递归法

#include <stdio.h>
#include <stdlib.h>
int a[60000],c=0;
int i;
int max(int m,int n)
{
    if(m>n)return m;
    else return n;
}
int sum(int ii,int jj)
{
    int maxsum=0;
    c++;
    if(ii==jj)
    {
        if(a[ii]>0)maxsum=a[ii];
        else
        {
            maxsum=0;
        }
    }
    else
    {
        int mid=(ii+jj)/2;
        int lsum=sum(ii,mid);
        int rsum=sum(mid+1,jj);
        int ss,s1,s2;
        s1=ss=0;
        for(i = mid; i>=ii; --i)
        {
            ss+=a[i];
            if(ss>s1)s1 = ss;
        }
        s2 = ss = 0;
        for(i = mid+1; i<=jj; ++i)
        {
            ss+=a[i];
            if(ss>s2)s2 = ss;
        }
        maxsum=s1+s2;
        maxsum=max(maxsum,lsum);
        maxsum=max(maxsum,rsum);
    }
    return maxsum;
}
int main()
{
    int n;
    scanf("%d",&n);
    for(i=0; i<n; i++)
    {
        scanf("%d",&a[i]);
    }
    int max1=sum(0,n-1);
    printf("%d %d\n",max1,c);
    return 0;
}