2015南阳CCPC C - The Battle of Chibi DP

#include <iostream>
#include <cstdio>
#include <cstring>
#include <cstdlib>
#include <cmath>
#include <algorithm>
#include <queue>
#include <map>
#include <set>
#include <vector>
#include <string>
#include <stack>
#include <bitset>
#define INF 1000000005
#define eps 1e-12
#define PI acos(-1.0)
#define LL long long

using namespace std;

const int maxn = 1005;
const int mod = 1000000007;
inline long long read()
{
    long long x=0,f=1;char ch=getchar();
    while(ch<‘0‘||ch>‘9‘){if(ch==‘-‘)f=-1;ch=getchar();}
    while(ch>=‘0‘&&ch<=‘9‘){x=x*10+ch-‘0‘;ch=getchar();}
    return x*f;
}
int a[maxn], b[maxn], c[maxn][maxn], n, m, dp[maxn][maxn];

inline void Init()
{
    for (int i = 1; i <= n; i++)
    {
        a[i] = b[i] = 0;
        for (int j = 1; j <= n; j++)
            dp[i][j] = c[i][j] = 0;
    }
    return;
}

inline int Lowbit(int x)
{
    return x & (- x);
}

inline void Update(int l, int pos, int key)
{
    while(pos <= n)
    {
        c[l][pos] = (c[l][pos] + key);
        while(c[l][pos]>=mod)
            c[l][pos] -= mod;
        pos = pos + Lowbit(pos);
    }
    return;
}

inline int Sum(int l, int pos)
{
    int temp = 0;
    while(pos)
    {
        temp = (temp + c[l][pos]);
        while(temp >= mod)temp -= mod;
        pos = pos - Lowbit(pos);
    }
    return temp;
}

int main()
{
    int T, cas = 0;
    scanf("%d", &T);
    while(T--)
    {
        scanf("%d%d", &n, &m);
        Init();
        for (int i = 1; i <= n; i++)
        {
            a[i]=read();
            //scanf("%d", &a[i]);
            b[i] = a[i];
        }
        sort(b + 1, b + 1 + n);
        for (int i = 1; i <= n; i++)
            a[i] = lower_bound(b + 1, b + 1 + n, a[i]) - b;
    //    cout << -1 << endl;
        for (int i = 1; i <= n; i++)
        {
           // cout << a[i] << endl;
            dp[i][1] = 1;
            for (int j = 2; j <= i; j++)
                dp[i][j] = Sum(j - 1, a[i] - 1);
            for (int j = 1; j <= i; j++)
                Update(j, a[i], dp[i][j]);
        }
        long long ans = 0;
        for (int i = 1; i <= n; i++)
            {
                ans = (ans + dp[i][m]);
                while(ans>=mod)
                    ans-=mod;// % mod;
                //cout << dp[i][m] << endl;
            }
        printf("Case #%d: %lld\n", ++cas, ans);
    }
    return 0;
}