zoukankan      html  css  js  c++  java
  • Sereja and Suffixes(思维)

    Sereja and Suffixes
    Time Limit:1000MS     Memory Limit:262144KB     64bit IO Format:%I64d & %I64u

    Description

    Sereja has an array a, consisting of n integers a1, a2, ..., an. The boy cannot sit and do nothing, he decided to study an array. Sereja took a piece of paper and wrote out m integers l1, l2, ..., lm(1 ≤ li ≤ n). For each number li he wants to know how many distinct numbers are staying on the positions li, li + 1, ..., n. Formally, he want to find the number of distinct numbers among ali, ali + 1, ..., an.?

    Sereja wrote out the necessary array elements but the array was so large and the boy was so pressed for time. Help him, find the answer for the described question for each li.

    Input

    The first line contains two integers n and m(1 ≤ n, m ≤ 105). The second line contains n integers a1, a2, ..., an(1 ≤ ai ≤ 105) — the array elements.

    Next m lines contain integers l1, l2, ..., lm. The i-th line contains integer li(1 ≤ li ≤ n).

    Output

    Print m lines — on the i-th line print the answer to the number li.

    Sample Input

    Input
    10 10 1 2 3 4 1 2 3 4 100000 99999 1 2 3 4 5 6 7 8 9 10
    Output
    6 6 6 6 6 5 4 3 2 1
    题解:让求x到n的不同数字的个数;打表,对于m次询问,如果每次都暴力肯定超了,由于n是固定的,所以打下表,从后往前;
    代码:
    #include<iostream>
    #include<cstdio>
    #include<cstring>
    #include<cmath>
    #include<algorithm>
    #include<set>
    #include<map>
    using namespace std;
    const int MAXN = 1e5+100;
    class Ary{
        public:
            int n,m;
            int a[MAXN];
            int dp[MAXN];
            set<int>st;
            Ary(int n,int m):n(n),m(m){
                for(int i = 1; i <= n; i++){
                    cin >> a[i];
                }
            }
            int work(){
                int cnt = 0;
                for(int i = n; i >= 1; i--){
                    if(!st.count(a[i])){
                        cnt++;
                        st.insert(a[i]);
                    }
                    dp[i] = cnt;
                }
                //cout << endl;
            }
            ~Ary(){
                //cout << "对象毁灭" << endl;
            }
    };
    int main(){
        int n,m;
        while(~scanf("%d%d", &n, &m)){
            Ary boy(n,m);
            int temp;
            boy.work();
            while(m--){
                scanf("%d",&temp);
                printf("%d
    ",boy.dp[temp]);
            }
        }
        return 0;
    }
  • 相关阅读:
    关于springboot项目使用yml类型的配置文件
    关于个人电脑连不上公司svn服务器,显示拒绝访问的错误
    改变思考问题的方式——SQL排序查询
    FreeMarker入门级
    个人电脑安装svn实录
    tomcat配置虚拟路径,可以解决实际开发中测试时前端访问后台电脑上的图片的问题
    springmvc的运行原理个人见解
    [CF915F] Imbalance Value of a Tree
    [CF768G] The Winds of Winter
    [BZOJ4241] 历史研究
  • 原文地址:https://www.cnblogs.com/handsomecui/p/5343909.html
Copyright © 2011-2022 走看看