Sort it(树状数组逆序对)
标签：ons i++ 逆序 mes names lse ref while color
http://acm.hdu.edu.cn/showproblem.php?pid=2689
#include#define low(x) (x&(-x))
using namespace std;
const int maxn=1e5+5;
typedef long long ll;
int a[maxn];
int n;
void add(int i,int d){
for(;i>0;i-=low(i))
a[i]+=d;
}
int ask(int i){
int cnt=0;
for(;ilow(i))
cnt+=a[i];
return cnt;
}
int main(){
//freopen("in","r",stdin);
while(scanf("%d",&n)!= EOF) {
ll ans = 0;
memset(a,0,sizeof(a));
for (int i = 1; i ) {
int num;
scanf("%d", &num);
ans += ask(num);
add(num, 1);
}
printf("%lld\n",ans);
}
return 0;
}
Sort it(树状数组逆序对)
标签：ons i++ 逆序 mes names lse ref while color
原文地址：https://www.cnblogs.com/xcfxcf/p/12979644.html
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