Codeforces Round #359 (Div. 2) B. Little Robber Girl's Zoo

题目链接：http://codeforces.com/contest/686/problem/B

B. Little Robber Girl's Zoo

time limit per test

2 seconds

memory limit per test

256 megabytes

input

standard input

output

standard output

Little Robber Girl likes to scare animals in her zoo for fun. She decided to arrange the animals in a row in the order of non-decreasing height. However, the animals were so scared that they couldn't stay in the right places.

The robber girl was angry at first, but then she decided to arrange the animals herself. She repeatedly names numbers l and r such thatr - l + 1 is even. After that animals that occupy positions between l and r inclusively are rearranged as follows: the animal at position lswaps places with the animal at position l + 1, the animal l + 2 swaps with the animal l + 3, ..., finally, the animal at position r - 1 swaps with the animal r.

Help the robber girl to arrange the animals in the order of non-decreasing height. You should name at most 20 000 segments, since otherwise the robber girl will become bored and will start scaring the animals again.

Input

The first line contains a single integer n (1 ≤ n ≤ 100) — number of animals in the robber girl's zoo.

The second line contains n space-separated integers a1, a2, ..., an (1 ≤ ai ≤ 109), where ai is the height of the animal occupying the i-th place.

Output

Print the sequence of operations that will rearrange the animals by non-decreasing height.

The output should contain several lines, i-th of the lines should contain two space-separated integers li and ri (1 ≤ li < ri ≤ n) — descriptions of segments the robber girl should name. The segments should be described in the order the operations are performed.

The number of operations should not exceed 20 000.

If the animals are arranged correctly from the start, you are allowed to output nothing.

Examples

input

4
2 1 4 3

output

1 4

input

7
36 28 57 39 66 69 68

output

1 4
6 7

input

5
1 2 1 2 1

output

2 5
3 4
1 4
1 4

Note

Note that you don't have to minimize the number of operations. Any solution that performs at most 20 000 operations is allowed.

题意

给你n个数，让你进行非递减排列，你可以对一个区间中的所有数字进行两两交换，区间大小是2的倍数即（r-l+1）是偶数（r l是你需要输出的），第一个数据1 4就是让第一个数和第二个数交换，第三个数和第四个数交换。

提示：你不用减少操作数量，能够执行20000次操作。（即不需要输出最少操作数量）

代码

#include <bits/stdc++.h>
using namespace std;
int main()
{
    int n,a,t,i,j;
    int z[105];
    cin>>n;
    for(a=0;n>a;a++){
        cin>>z[a];
    }
    i=0;
    j=1;
    for(;j<n;){
        if(z[i]>z[j]){
            cout<<i+1<<" "<<j+1<<endl;
            t=z[i];
            z[i]=z[j];
            z[j]=t;
            if(z[i-1]>z[i]&&i-1>=0){
                i--;
                j--;
                continue;
            }
            i++;
            j++;
        }
        else{
            i++;
            j++;
        }
    }
    return 0;
}