HDU5806 NanoApe Loves Sequence Ⅱ (BestCoder Round #86 C)二分

#include <cstdio>
#include <cstring>
#include <cmath>
#include <algorithm>
using namespace std;
typedef long long LL;
const int N = 2e5+5;
int T,n,m,k,a[N],sum[N];
int main(){
  scanf("%d",&T);
  while(T--){
    scanf("%d%d%d",&n,&m,&k);
    for(int i=1;i<=n;++i){
     scanf("%d",&a[i]);
     if(a[i]>=m)a[i]=1;
     else a[i]=0; 
    }
    for(int i=1;i<=n;++i)sum[i]=sum[i-1]+a[i];
    LL ret=0;
    for(int i=1;i<=n;++i){
       if(n-i+1<k)break;
       if(sum[n]-sum[i-1]<k)break;
       int l=i+k-1,r=n;
       while(l<r){
         int mid=(l+r)>>1;
         if(sum[mid]-sum[i-1]>=k)r=mid;
         else l=mid+1;
       }
       int tmp=(l+r)>>1;
       ret+=(n-tmp+1);
    }
    printf("%I64d\n",ret); 
  }
  return 0;
}