zoukankan      html  css  js  c++  java
  • Gym 100952 D. Time to go back

    D. Time to go back
    time limit per test
    1 second
    memory limit per test
    256 megabytes
    input
    standard input
    output
    standard output

    You have been out of Syria for a long time, and you recently decided to come back. You remember that you have M friends there and since you are a generous man/woman you want to buy a gift for each of them, so you went to a gift store that have N gifts, each of them has a price.

    You have a lot of money so you don't have a problem with the sum of gifts' prices that you'll buy, but you have K close friends among your M friends you want their gifts to be expensive so the price of each of them is at least D.

    Now you are wondering, in how many different ways can you choose the gifts?

    Input

    The input will start with a single integer T, the number of test cases. Each test case consists of two lines.

    the first line will have four integers N, M, K, D (0  ≤  N, M  ≤  200, 0  ≤  K  ≤  50, 0  ≤  D  ≤  500).

    The second line will have N positive integer number, the price of each gift.

    The gift price is  ≤  500.

    Output

    Print one line for each test case, the number of different ways to choose the gifts (there will be always one way at least to choose the gifts).

    As the number of ways can be too large, print it modulo 1000000007.

    Examples
    Input
    2
    5 3 2 100
    150 30 100 70 10
    10 5 3 50
    100 50 150 10 25 40 55 300 5 10
    Output
    3
    126
    商店有n件商品,有m个朋友。其中又有k个十分亲密的朋友,十分亲密的朋友的礼物价值不得低于d,显然是一个排列组合,但数据量大,构造组合函数精度容易出问题,因此可以用杨辉三角
    vis[i][j]=vis[i-1][j-1]+vis[i-1][j];
    #include <iostream>
    #include <cstdio>
    #include <cstring>
    #include <queue>
    #include <cmath>
    #include <map>
    #include <vector>
    #include <algorithm>
    using namespace std;
    #define lowbit(x) (x&(-x))
    #define max(x,y) (x>y?x:y)
    #define min(x,y) (x<y?x:y)
    #define MAX 100000000000000000
    #define MOD 1000000007
    #define PI 3.141592653589793238462
    #define INF 0x3f3f3f3f3f
    #define mem(a) (memset(a,0,sizeof(a)))
    typedef long long ll;
    ll vis[210][210],val[210],n,m,k,d,t;
    bool cmp(int a,int b)
    {
        return a>b;
    }
    int main()
    {
        mem(vis);
        for(int i=0;i<210;i++)
        {
            vis[i][0]=1;
            for(int j=1;j<=i;j++)
            {
                vis[i][j]=(((vis[i-1][j-1])%MOD)+((vis[i-1][j])%MOD))%MOD;
            }
        }
        scanf("%lld",&t);
        while(t--)
        {
            ll ans=0,pos=0;
            scanf("%lld%lld%lld%lld",&n,&m,&k,&d);
            for(ll i=0;i<n;i++)
                scanf("%lld",&val[i]);
            sort(val,val+n,cmp);
            for(ll i=0;i<n;i++)
            {
                if(val[i]>=d) ans++;
                else break;
            }
            if(n-ans==0) pos=vis[ans][m];
            else if(ans<k || n<m) pos=0;
            else
            {
                for(ll i=k;i<=ans;i++)
                {
                    if(m-i<0) break;
                    pos=(pos+(vis[ans][i]*vis[n-ans][m-i])%MOD)%MOD;
                }
            }
            printf("%lld
    ",pos);
        }
    }
  • 相关阅读:
    Spring AOP概念理解 (通俗易懂)【转】
    【转】Spring AOP四种实现方式Demo详解与相关知识探究
    call的理解
    队列的执行顺序
    数组去重的方法
    要动态改变层中的内容的方法
    HTML5有哪些新特性,移除了哪些元素?如何处理HTML5新标签的浏览器兼容性问题?如何区分HTML和HTML5
    行内元素有哪些?块级元素有哪些? 空(void)元素有那些?
    HTML5头部为什么只需要写<!DOCTYPE HTML>
    link和@import引入外部样式的区别
  • 原文地址:https://www.cnblogs.com/shinianhuanniyijuhaojiubujian/p/7199223.html
Copyright © 2011-2022 走看看