BestCoder Round #86 1003

链接：http://acm.hdu.edu.cn/showproblem.php?pid=5806

题意：有多少个区间里的第

解法：尺取法，首先我们用dp[i]保存到i的位置有多少大于m的数

l=1，r=1，r开始遍历,只要符合dp[l]-dp[r]==k就是sum+=（n-r+1）

然后根据情况移动l,r

#include<stdio.h>
//#include<bits/stdc++.h>
#include<string.h>
#include<iostream>
#include<math.h>
#include<sstream>
#include<set>
#include<queue>
#include<map>
#include<vector>
#include<algorithm>
#include<limits.h>
#define inf 0x3fffffff
#define INF 0x3f3f3f3f
#define lson l,m,rt<<1
#define rson m+1,r,rt<<1|1
#define LL long long
#define ULL unsigned long long
using namespace std;
long long n,m,k;
long long a[100005];
long long q,p;
long long b[100005],e[100005],c[100005];
long long dp[200005];
long long sum=0;
int t;
long long MAXN1,MAXN2;
int main()
{
    scanf("%d",&t);
    while(t--)
    {
        sum=0;
        int j=0;
        memset(dp,0,sizeof(dp));
        scanf("%d%d%d",&n,&m,&k);
        for(int i=1;i<=n;i++)
        {
            scanf("%d",&a[i]);
        }
        for(int i=1;i<=n;i++)
        {
            if(a[i]>=m)
            {
                dp[i]=dp[i-1]+1;
            }
            else
            {
                dp[i]=dp[i-1];
            }
           // cout<<dp[i]<<"A"<<endl;
        }
        int i=1;
        while(i<=n)
        {
            while(dp[i]-dp[j]==k)
            {
                sum+=(n-i+1);
                j++;
            }
            i++;
        }
        printf("%lld\n",sum);
    }
    return 0;
}