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Codeforces Round #215 (Div. 2) B. Sereja and Suffixes

2013-12-13 12:53 393 查看
B. Sereja and Suffixes

time limit per test
1 second

memory limit per test
256 megabytes

input
standard input

output
standard output

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 test(s)

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


一道简单的题 ,用dp的思想

#include <iostream>
#include <set>
#include <cstdio>
using namespace std;

const int maxn=100000;
int n,m,a[maxn+10],dp[maxn+10];
set <int> mys;

void initial(){
mys.clear();
}

void input(){
for(int i=0;i<n;i++){
scanf("%d",&a[i]);
dp[i]=0;
}
}

void computing(){
for(int i=n-1;i>=0;i--){
mys.insert(a[i]);
dp[i]=mys.size();
}
int l;
while(m-- >0){
scanf("%d",&l);
printf("%d\n",dp[l-1]);
}
}

int main(){
while(scanf("%d%d",&n,&m)!=EOF){
initial();
input();
computing();
}
return 0;
}
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