标签：cas -- hat wap str operation enc ppi case
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
Ultra-QuickSort produces the output
Your task is to determine how many swap operations Ultra-QuickSort needs to perform in order to sort a given input sequence.Input
Output
Sample Input
5 9 1 0 5 4 3 1 2 3 0
Sample Output
6 0
题目的意思是求一个数列的逆序数，用树状数组可以直接模拟出来。
1 #include<iostream> 2 #include<cstdio> 3 #include<cstring> 4 #include<algorithm> 5 6 using namespace std; 7 8 const int maxn=500005; 9 int c[maxn],d[maxn],g[maxn]; 10 11 void update(int x,int v) 12 { 13 for(;x<=maxn;x+=x&(-x)) 14 g[x]+=v; 15 } 16 17 int getsum(int x) 18 { 19 int sum=0; 20 for(;x>0;x-=x&(-x)) 21 sum+=g[x]; 22 return sum; 23 } 24 25 int main() 26 { 27 int n; 28 while(~scanf("%d",&n),n) 29 { 30 memset(c,0,sizeof(c)); 31 memset(d,0,sizeof(d)); 32 memset(g,0,sizeof(g)); 33 for(int i=0;i<n;i++) 34 { 35 scanf("%d",&c[i]); 36 d[i]=c[i]; 37 } 38 sort(d,d+n); 39 int size=unique(d,d+n)-d; 40 for(int i=0;i<n;i++) 41 c[i]=lower_bound(d,d+n,c[i])-d+1; 42 /*for(int i=1;i<=n;i++) 43 cout<<c[i]<<" ";*/ 44 long long ans=0; 45 for(int i=0;i<n;i++) 46 { 47 update(c[i],1); 48 ans+=i+1-getsum(c[i]); 49 } 50 printf("%lld\n",ans); 51 } 52 53 54 return 0; 55 }
标签：cas -- hat wap str operation enc ppi case
原文地址：http://www.cnblogs.com/xibeiw/p/7371371.html
