Description
In this problem, you have to analyze a particular sorting algorithm. The algorithm processes a sequence of n distinct integers by swapping two adjacent sequence elements until the sequence is sorted in ascending order. For the input sequence
9 1 0 5 4 ,
Ultra-QuickSort produces the output
0 1 4 5 9 .
Your task is to determine how many swap operations Ultra-QuickSort needs to perform in order to sort a given input sequence.
Input
The input contains several test cases. Every test case begins with a line that contains a single integer n < 500,000 -- the length of the input sequence. Each of the the following n lines contains a single integer 0 ≤ a[i] ≤ 999,999,999, the i-th input sequence element. Input is terminated by a sequence of length n = 0. This sequence must not be processed.
Output
For every input sequence, your program prints a single line containing an integer number op, the minimum number of swap operations necessary to sort the given input sequence.
Sample Input
59 1 0 5 4 3 1 2 3 0
Sample Output
60
Source
线段树
#include<stdio.h>
#include<iostream>
#include<string.h>
#include<algorithm>
using namespace std;
struct ele
{
__int64 x;
__int64 num;
}a[502211];
__int64 c[502211];
bool cmp(ele x,ele y)
{
return x.x<y.x;
}
struct Ele
{
int left;
int right;
__int64 sum;
}p[2501122];
void build(int x,int y,int step)
{
p[step].left=x;
p[step].right=y;
p[step].sum=0;
if(p[step].right==p[step].left)
return;
else
{
int Mid=(p[step].right+p[step].left)/2;
build(x,Mid,2*step);
build(Mid+1,y,2*step+1);
}
}
void update(int x,int step)
{
if(p[step].right==p[step].left)
p[step].sum=1;
else
{
int Mid=(p[step].right+p[step].left)/2;
if(x<=Mid)
update(x,2*step);
else
update(x,2*step+1);
p[step].sum=p[step*2].sum+p[step*2+1].sum;
}
}
__int64 get(int x,int y,int step)
{
if(p[step].right==y&&p[step].left==x)
return p[step].sum;
else
{
int Mid=(p[step].right+p[step].left)/2;
if(y<=Mid)
return get(x,y,2*step);
else
if(x>=Mid+1)
return get(x,y,2*step+1);
else
return get(x,Mid,2*step)+get(Mid+1,y,2*step+1);
}
}
int main()
{
int n;
int i;
while(scanf("%d",&n),n)
{
for(i=1;i<=n;i++)
{
scanf("%I64d",&c[i]);
a[i].num=i;
a[i].x=c[i];
}
sort(a+1,a+n+1,cmp);
int num=1;
__int64 temp=a[1].x;
for(i=1;i<=n;i++)
{
if(a[i].x!=temp)
{
temp=a[i].x;
num++;
}
c[a[i].num]=num;
}
build(1,num,1);
__int64 sum=0;
for(i=1;i<=n;i++)
{
if(c[i]+1<=num)
{
sum+=get(c[i]+1,num,1);
//printf("%d\n",get(c[i]));
}
update(c[i],1);
}
printf("%I64d\n",sum);
}
return 0;
}
#include<stdio.h>
int a[501122];
int b[501122];
int c[501122];
__int64 sum;
void Merge(int x,int y,int z)
{
int i,j,k;
for(i=x;i<=y;i++)
b[i]=a[i];
for(i=y+1;i<=z;i++)
c[i]=a[i];
i=x;
j=y+1;
k=x;
while(i<=y&&j<=z)
{
if(b[i]<c[j])
{
a[k]=b[i];
i++;
k++;
}
else
{
sum+=(y-i+1);
a[k]=c[j];
j++;
k++;
}
}
while(i<=y)
{
a[k]=b[i];
i++;
k++;
}
while(j<=z)
{
a[k]=c[j];
k++;
j++;
}
}
void Sort(int x,int y)
{
if(x<y)
{
Sort(x,(x+y)/2);
Sort((x+y)/2+1,y);
Merge(x,(x+y)/2,y);
}
}
int main()
{
int n;
int i;
int Begin,End;
while(scanf("%d",&n),n)
{
sum=0;
for(i=1;i<=n;i++)
scanf("%d",&a[i]);
Begin=1;
End=n;
Sort(Begin,End);
printf("%I64d\n",sum);
}
return 0;
}
