通过代码来学习例子看下面代码:
//点结构
typedef struct Pair
{
x ;
y ;
} Pair ;
//最近点对结构
typedef struct Closest_Pair
{
Pair pair_a ,pair_b ;
double distance ;
} Closest_Pair ;
//点对结构
typedef struct Pos
{
Pair* p_pair ;
pair_nums ;//点对数目
} Pos
//蛮力法:分别计算每对点的间距离然后找距离最小那对
bool Brute_Force(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
for( i=from ;i<=to ;i)
{
for( j=i+1;j<=to ;j)
{
double next= Account_Distance_2(pos.p_pair[i] ,pos.p_pair[j]) ; (closest_pair.distance > next )
{
closest_pair.pair_a = pos.p_pair[i] ;
closest_pair.pair_b = pos.p_pair[j] ;
closest_pair.distance = next ;
}
}
}
true ;
}
//分治法:遵循分治思路方法利用递归求出左子集和右子集最近点对然后再对两子集的间点对进步分析比较最后求出整个点集最近点对
void Divide_and_Conquer(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
( (to-from+1) <4 )
{
Brute_Force(pos ,closest_pair ,from ,to ) ;
cout << "<4 " << closest_pair.distance << endl ;
//system("pause") ;
}
{
mid = (from+to)/2 ;
mid_value = pos.p_pair[mid].x ;
Divide_and_Conquer(pos ,closest_pair ,from ,mid) ;
Divide_and_Conquer(pos ,closest_pair ,mid+1 ,to) ;
Comp_CP(pos ,closest_pair ,mid ,mid_value) ;
}
;
}
# "Head.h"
//---------------------------------------------------------------------------
typedef RedType ;
typedef struct Pair
{
x ;
y ;
} Pair ;
typedef struct Closest_Pair
{
Pair pair_a ,pair_b ;
double distance ;
} Closest_Pair ;
typedef struct Pos
{
Pair* p_pair ;
pair_nums ;//点对数目
} Pos ;
//---------------------------------------------------------------------------
Pos pos ;
Closest_Pair closest_pair ;
// pair_nums ;
//---------------------------------------------------------------------------
double Account_Distance_2(const Pair& A ,const Pair& B )
{
( (A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y) ) ;
}
//---------------------------------------------------------------------------
void Pr_Pos(ostream& outs ,const Pos& pos ,const Closest_Pair& closest_pair )
{
outs << "\n\n\n 随机产生点对如下:\n" ;
for( i=0 ;i<pos.pair_nums ;i)
{
outs << " (" << pos.p_pair[i].x << " , " << pos.p_pair[i].y << " ) " ;
((i+1)%50)
{
outs << endl ;
}
}
outs << "\n\n 由以上点对可得最近点对为: ( "
<< closest_pair.pair_a.x << " , " << closest_pair.pair_a.y << " ) ,( "
<< closest_pair.pair_b.x << " , " << closest_pair.pair_b.y << " ) " ;
outs << "\n 该点对距离为:" << closest_pair.distance << endl ;
}
//---------------------------------------------------------------------------
bool Brute_Force(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
for( i=from ;i<=to ;i)
{
for( j=i+1;j<=to ;j)
{
double next = Account_Distance_2(pos.p_pair[i] ,pos.p_pair[j]) ;//sqrt( )
(closest_pair.distance > next )
{
closest_pair.pair_a = pos.p_pair[i] ;
closest_pair.pair_b = pos.p_pair[j] ;
closest_pair.distance = next ;
}
}
}
true ;
}
//--------------------------------------------------------------------------
// 对顺序表L作归并排序
void Merge(char sign ,Pair SR ,Pair TR ,long i ,long m ,long n)
{ // 将有序SR[i..m]和SR[m+1..n]归并为有序TR[i..n]
// j,k,l;
for( j=m+1,k=i;i<=m&&j<=n;k) // 将SR中记录由小到大地并入TR
{
(sign'x')
{
( SR[i].x < SR[j].x )
TR[k]=SR[i];
TR[k]=SR[j];
}
{
( SR[i].y < SR[j].y )
TR[k]=SR[i];
TR[k]=SR[j];
}
}
(i<=m)
{
for( l=0;l<=m-i;l)
{
TR[k+l]=SR[i+l]; // 将剩余SR[i..m]复制到TR
}
}
{
for( l=0;l<=n-j;l)
{
TR[k+l]=SR[j+l]; // 将剩余SR[j..n]复制到TR
}
}
}
//---------------------------------------------------------------------------
void MSort(char sign ,Pair SR ,Pair TR1 ,long s , long t)
{ // 将SR[s..t]归并排序为TR1[s..t].
(st)
{
TR1[s] = SR[s];
}
{
// m ;
length = t-s+1 ;//
Pair* TR2 = Pair[pos.pair_nums];
long m = (s+t)/2; // 将SR[s..t]平分为SR[s..m]和SR[m+1..t]
MSort(sign ,SR,TR2,s,m) ; // 递归地将SR[s..m]归并为有序TR2[s..m]
MSort(sign ,SR,TR2,m+1,t) ; // 递归地将SR[m+1..t]归并为有序TR2[m+1..t]
Merge(sign ,TR2,TR1,s,m,t) ; // 将TR2[s..m]和TR2[m+1..t]归并到TR1[s..t]
delete TR2 ;
}
// cout << " Hello " ;
}
//---------------------------------------------------------------------------
void Comp_CP(const Pos& pos ,Closest_Pair& closest_pair , mid , mid_value)
{
i , j ;
distance = sqrt( closest_pair.distance ) ;
i = mid ;
while( i >= 0 && pos.p_pair[i].x > (mid_value-distance) )
{
j = mid ;
while( pos.p_pair[j].x < (mid_value+distance) && j < pos.pair_nums )
{
( pos.p_pair[j].y > (pos.p_pair[i].y+distance) ||
pos.p_pair[j].y < (pos.p_pair[i].y-distance) )
//判断在y轴是否出界
continue ;
double next = Account_Distance_2( pos.p_pair[i] ,pos.p_pair[j]);//sqrt( )
(closest_pair.distance > next )
{
closest_pair.pair_a = pos.p_pair[i] ;
closest_pair.pair_b = pos.p_pair[j] ;
closest_pair.distance = next ;
cout << "Comp_CP: " << closest_pair.distance << endl ;
}
}
i-- ;
}
}
//---------------------------------------------------------------------------
void Divide_and_Conquer(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
( (to-from+1) <4 )
{
Brute_Force(pos ,closest_pair ,from ,to ) ;
cout << "<4 " << closest_pair.distance << endl ;
//system("pause") ;
}
{
mid = (from+to)/2 ;
mid_value = pos.p_pair[mid].x ;
Divide_and_Conquer(pos ,closest_pair ,from ,mid) ;
Divide_and_Conquer(pos ,closest_pair ,mid+1 ,to) ;
Comp_CP(pos ,closest_pair ,mid ,mid_value) ;
}
;
}
//---------------------------------------------------------------------------
void
{
time_t t;
srand((unsigned) time(&t));
char c ;
do
{
system("cls") ;
cout << "\n\n 请输入你要随机产生点对对数: " ;
cin >> pos.pair_nums ;
pos.p_pair = Pair[pos.pair_nums] ;
for( i=0 ;i<pos.pair_nums ;i)
{
pos.p_pair[i].x= rand%101 ;
pos.p_pair[i].y= rand%101 ;
}
//分治法求解先排序
MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
/*//
*/
//蛮力法求解
closest_pair.distance = 32676 ;//MAX_SIZE
Brute_Force(pos ,closest_pair ,0 ,pos.pair_nums-1 ) ;
closest_pair.distance = sqrt( closest_pair.distance ) ;
Pr_Pos( cout , pos ,closest_pair ) ;
//分治法求解先排序
//MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
//分治法求解
closest_pair.distance = 32676 ;//MAX_SIZE
Divide_and_Conquer(pos ,closest_pair ,0 ,pos.pair_nums-1 ) ;
closest_pair.distance = sqrt( closest_pair.distance ) ;
Pr_Pos( cout , pos ,closest_pair ) ;
//MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
// Pr_Pos( cout , pos ,closest_pair ) ;
cout << "\n\n !!!按任意键继续Esc退出!!!" << endl ;
}while( (c=getch)!=27 ) ;
;
}
//---------------------------------------------------------------------------
# "Head.h"
//---------------------------------------------------------------------------
typedef RedType ;
typedef struct Pair
{
x ;
y ;
} Pair ;
typedef struct Closest_Pair
{
Pair pair_a ,pair_b ;
double distance ;
} Closest_Pair ;
typedef struct Pos
{
Pair* p_pair ;
pair_nums ;//点对数目
} Pos ;
//---------------------------------------------------------------------------
Pos pos ;
Closest_Pair closest_pair ;
// pair_nums ;
//---------------------------------------------------------------------------
double Account_Distance_2(const Pair& A ,const Pair& B )
{
( (A.x-B.x)*(A.x-B.x)+(A.y-B.y)*(A.y-B.y) ) ;
}
//---------------------------------------------------------------------------
void Pr_Pos(ostream& outs ,const Pos& pos ,const Closest_Pair& closest_pair )
{
outs << "\n\n\n 随机产生点对如下:\n" ;
for( i=0 ;i<pos.pair_nums ;i)
{
outs << " (" << pos.p_pair[i].x << " , " << pos.p_pair[i].y << " ) " ;
((i+1)%50)
{
outs << endl ;
}
}
outs << "\n\n 由以上点对可得最近点对为: ( "
<< closest_pair.pair_a.x << " , " << closest_pair.pair_a.y << " ) ,( "
<< closest_pair.pair_b.x << " , " << closest_pair.pair_b.y << " ) " ;
outs << "\n 该点对距离为:" << closest_pair.distance << endl ;
}
//---------------------------------------------------------------------------
bool Brute_Force(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
for( i=from ;i<=to ;i)
{
for( j=i+1;j<=to ;j)
{
double next = Account_Distance_2(pos.p_pair[i] ,pos.p_pair[j]) ;//sqrt( )
(closest_pair.distance > next )
{
closest_pair.pair_a = pos.p_pair[i] ;
closest_pair.pair_b = pos.p_pair[j] ;
closest_pair.distance = next ;
}
}
}
true ;
}
//--------------------------------------------------------------------------
// 对顺序表L作归并排序
void Merge(char sign ,Pair SR ,Pair TR ,long i ,long m ,long n)
{ // 将有序SR[i..m]和SR[m+1..n]归并为有序TR[i..n]
// j,k,l;
for( j=m+1,k=i;i<=m&&j<=n;k) // 将SR中记录由小到大地并入TR
{
(sign'x')
{
( SR[i].x < SR[j].x )
TR[k]=SR[i];
TR[k]=SR[j];
}
{
( SR[i].y < SR[j].y )
TR[k]=SR[i];
TR[k]=SR[j];
}
}
(i<=m)
{
for( l=0;l<=m-i;l)
{
TR[k+l]=SR[i+l]; // 将剩余SR[i..m]复制到TR
}
}
{
for( l=0;l<=n-j;l)
{
TR[k+l]=SR[j+l]; // 将剩余SR[j..n]复制到TR
}
}
}
//---------------------------------------------------------------------------
void MSort(char sign ,Pair SR ,Pair TR1 ,long s , long t)
{ // 将SR[s..t]归并排序为TR1[s..t].
(st)
{
TR1[s] = SR[s];
}
{
// m ;
length = t-s+1 ;//
Pair* TR2 = Pair[pos.pair_nums];
long m = (s+t)/2; // 将SR[s..t]平分为SR[s..m]和SR[m+1..t]
MSort(sign ,SR,TR2,s,m) ; // 递归地将SR[s..m]归并为有序TR2[s..m]
MSort(sign ,SR,TR2,m+1,t) ; // 递归地将SR[m+1..t]归并为有序TR2[m+1..t]
Merge(sign ,TR2,TR1,s,m,t) ; // 将TR2[s..m]和TR2[m+1..t]归并到TR1[s..t]
delete TR2 ;
}
// cout << " Hello " ;
}
//---------------------------------------------------------------------------
void Comp_CP(const Pos& pos ,Closest_Pair& closest_pair , mid , mid_value)
{
i , j ;
distance = sqrt( closest_pair.distance ) ;
i = mid ;
while( i >= 0 && pos.p_pair[i].x > (mid_value-distance) )
{
j = mid ;
while( pos.p_pair[j].x < (mid_value+distance) && j < pos.pair_nums )
{
( pos.p_pair[j].y > (pos.p_pair[i].y+distance) ||
pos.p_pair[j].y < (pos.p_pair[i].y-distance) )
//判断在y轴是否出界
continue ;
double next = Account_Distance_2( pos.p_pair[i] ,pos.p_pair[j]);//sqrt( )
(closest_pair.distance > next )
{
closest_pair.pair_a = pos.p_pair[i] ;
closest_pair.pair_b = pos.p_pair[j] ;
closest_pair.distance = next ;
cout << "Comp_CP: " << closest_pair.distance << endl ;
}
}
i-- ;
}
}
//---------------------------------------------------------------------------
void Divide_and_Conquer(const Pos& pos ,Closest_Pair& closest_pair , from , to)
{
( (to-from+1) <4 )
{
Brute_Force(pos ,closest_pair ,from ,to ) ;
cout << "<4 " << closest_pair.distance << endl ;
//system("pause") ;
}
{
mid = (from+to)/2 ;
mid_value = pos.p_pair[mid].x ;
Divide_and_Conquer(pos ,closest_pair ,from ,mid) ;
Divide_and_Conquer(pos ,closest_pair ,mid+1 ,to) ;
Comp_CP(pos ,closest_pair ,mid ,mid_value) ;
}
;
}
//---------------------------------------------------------------------------
void
{
time_t t;
srand((unsigned) time(&t));
char c ;
do
{
system("cls") ;
cout << "\n\n 请输入你要随机产生点对对数: " ;
cin >> pos.pair_nums ;
pos.p_pair = Pair[pos.pair_nums] ;
for( i=0 ;i<pos.pair_nums ;i)
{
pos.p_pair[i].x= rand%101 ;
pos.p_pair[i].y= rand%101 ;
}
//分治法求解先排序
MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
/*//
*/
//蛮力法求解
closest_pair.distance = 32676 ;//MAX_SIZE
Brute_Force(pos ,closest_pair ,0 ,pos.pair_nums-1 ) ;
closest_pair.distance = sqrt( closest_pair.distance ) ;
Pr_Pos( cout , pos ,closest_pair ) ;
//分治法求解先排序
//MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
//分治法求解
closest_pair.distance = 32676 ;//MAX_SIZE
Divide_and_Conquer(pos ,closest_pair ,0 ,pos.pair_nums-1 ) ;
closest_pair.distance = sqrt( closest_pair.distance ) ;
Pr_Pos( cout , pos ,closest_pair ) ;
//MSort('x' ,pos.p_pair ,pos.p_pair ,0 ,pos.pair_nums-1 ) ;
// Pr_Pos( cout , pos ,closest_pair ) ;
cout << "\n\n !!!按任意键继续Esc退出!!!" << endl ;
}while( (c=getch)!=27 ) ;
;
}
//---------------------------------------------------------------------------
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