一道面试题（算法）

[good_9901]

打印一整数N的正整数组合（递减）
如3有2+1或1+1+1两种组合；

[good_9901]

up

[vcmute]

unsigned char a[100] = {0};
bool fill(int j,int N)
{
for(int i=j;i<N;++i)
if((a[j-1]>a[i]+1))
{
--a[j-1];
++a[i];
return true;
}
return false;
}

int main(int argc, char* argv[])
{
int M = 3;
for(int N=1;N<=M;N++)
{
memset(a,1,N);
a[0] += M-N;
int k = 1;
while(k)
{
for(int i=0;i<N;++i)
printf("%5d",a[i]);
//show();
printf("\n");
while(!fill(k,N))
if(--k<1)
break;
if(k>=1)
++k;
}
}
}

[WindYou]

typedef struct
{
int curPos;
int buf[1];
}Data;

typedef struct _link
{
_link *next;
int count;
int buf[1];
}Link;

Link * head = NULL;

Link * NewLink(int count, int *buf)
{
Link * link = (Link *)malloc((count + 1) * sizeof(int) + sizeof(Link *));
link->count = count;
memcpy(link->buf, buf, sizeof(int)*count);
link->next = NULL;
return link;
}

void Sort(int *buf, int len)
{
for(int i = 0; i < len - 1; i++)
{
for(int j = len - 1; j > i; j--)
{
if(buf[i] < buf[j])
{
int temp = buf[i];
buf[i] = buf[j];
buf[j] = temp;
}
}
}
}

void getSub(unsigned int val, Data *data)
{
bool Catched = false;
if( val == 1 )
{
data->buf[data->curPos] = 1;
data->curPos++;
Catched = true;
}
else if( !val )
{
Catched = true;
}

if( Catched )
{
Link *curlink = head;
Link * link = NewLink(data->curPos, data->buf);
Sort(link->buf, link->count);
while( curlink )
{
if( curlink->count == link->count )
{
if( !memcmp(curlink->buf, link->buf, link->count) ) break;
}
curlink = curlink->next;
}

if( !curlink )
{
if( !head )
{
head = link;
}
else
{
curlink = head;
while( curlink->next )
{
curlink = curlink->next;
}
curlink->next = link;
}
cout << "\n一个组合:\n";
for(int i = 0; i < data->curPos; i++)
{
cout << data->buf[i] << "\t";
}
}
}
else
{
int curpos = data->curPos;
for(int n = val; n > 0 ; n--)
{
data->curPos = curpos;
data->buf[curpos] = n;
data->curPos++;

getSub(val - n, data);
}
}
}



int main(int argc, char* argv[])
{
unsigned int value = 1;

while( value )
{
cout << "输入一个正整数：";
cin >> value;

Data *data = (Data *)malloc( (value + 1) * sizeof(int) );
data->curPos = 0;

getSub(value, data);

cout << endl;

Link * nextlink;

while( head )
{
nextlink = head->next;
free( head );
head = nextlink;
}
free( data );
}
}

[WindYou]

上面的排除了相同的组合.

[billy145533]

高程的辅导书里就有这么一道

[erben]

o

[yangbc]

这两个算法都不行

[FengYuanMSFT]

static void Divide(int n, int max, string prefix)
{
if (n == 0)
{
Console.WriteLine(prefix);
}
else
{
for (int i = max; i > 0; i --)
{
if (n >= i)
{
if (prefix != null)
{
Divide(n - i, i, prefix + " + " + i);
}
else
{
Divide(n - i, i, i.ToString());
}
}
}
}
}

static void Divide(int n)
{
Divide(n, n - 1, null);
}

[booming]

so easy

[sdgzhk]

有个问题。如果是6。那4+2行不行？