http://acm.hdu.edu.cn/showproblem.php?pid=4217
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1 #include <cstdio> 2 #include <cstring> 3 using namespace std; 4 5 typedef __int64 LL; 6 const int N=270000; 7 int c[N]; 8 int lowbit(int x) 9 { 10 return x&(-x); 11 } 12 void add(int x,int p,int maxn) 13 { 14 for(int i=p;i<=maxn;i+=lowbit(i)) c[i]+=x; 15 } 16 int sum(int x) 17 { 18 int s=0; 19 for(int i=x;i>0;i-=lowbit(i)) s+=c[i]; 20 return s; 21 } 22 int lowbound(int x,int l,int r) 23 { 24 while(l<r) 25 { 26 int m=(l+r)/2; 27 if(sum(m)<x) l=m+1; 28 else r=m; 29 } 30 return l; 31 } 32 int main() 33 { 34 int T,C=0; 35 scanf("%d",&T); 36 while(T--) 37 { 38 memset(c,0,sizeof(c)); 39 int n,k; 40 scanf("%d%d",&n,&k); 41 for(int i=1;i<=n;i++) add(1,i,n); 42 LL ans=0; 43 while(k--) 44 { 45 int x; 46 scanf("%d",&x); 47 int p=lowbound(x,1,n); 48 ans+=p; 49 add(-1,p,n); 50 } 51 printf("Case %d: %I64d\n",++C,ans); 52 } 53 return 0; 54 }
