CF2052A Adrenaline Rush · znzryb

## 思路讲解

[https://codeforces.com/contest/2052/submission/297107696](https://codeforces.com/contest/2052/submission/297107696)

jianly的思路我觉得比官解更好（官解都看不懂是什么意思）

jianly的思路就是逆向思维，先将345612（这是输入进来的）转化为654321，再将654321转化为123456

整个过程我们都记录下来，reverse一下输出即可。

## AC代码

[https://codeforces.com/contest/2052/submission/311474567](https://codeforces.com/contest/2052/submission/311474567)

```cpp
// Problem: CF2052A Adrenaline Rush
// Contest: Luogu
// URL: https://www.luogu.com.cn/problem/CF2052A
// Memory Limit: 1000 MB
// Time Limit: 3000 ms
// by znzryb
// 
// Powered by CP Editor (https://cpeditor.org)

#include <bits/stdc++.h>
#define FOR(i, a, b) for (int i = (a); i <= (b); ++i)
#define ROF(i, a, b) for (int i = (a); i >= (b); --i)
#define all(x) x.begin(),x.end()
#define CLR(i,a) memset(i,a,sizeof(i))
#define fi first
#define se second
#define pb push_back
#define SZ(a) ((int) a.size())

using namespace std;

typedef long long ll;
typedef unsigned long long ull;
typedef pair<ll,ll> pll;
typedef array<ll,3> arr;
typedef double DB;
typedef pair<DB,DB> pdd;
constexpr ll MAXN=static_cast<ll>(1e3)+10,INF=static_cast<ll>(5e18)+3;

ll N,M,C[MAXN];

inline void solve(){
	cin>>N;
	FOR(i,1,N){
		cin>>C[i];
	}
	vector<pll> ans;
	// 先将345612（这是输入进来的）转化为654321
	ROF(i,N,1){
		ll pi=0;
		FOR(j,1,N){
			if(C[j]==i){
				pi=j;
				break;
			}
		}
		ROF(j,pi-1,1){
			if(C[j]<C[j+1]){
				// 不仅顺序最后要倒过来，超车顺序也要倒过来
				ans.pb({C[j],C[j+1]});
				swap(C[j],C[j+1]);
			}
		}
	}
	FOR(i,1,N){
		FOR(j,i+1,N){
			ans.pb({j,i});
		}
	}
	reverse(ans.begin(),ans.end());
	cout<<SZ(ans)<<"\n";
	FOR(i,0,SZ(ans)-1){
		cout<<ans[i].fi<<" "<<ans[i].se<<"\n";
	}
// #ifdef LOCAL
    // FOR(i,1,N){
    	// cerr<<C[i]<<" ";
    // }
    // cerr<<"\n";
// #endif
}

int main()
{
	ios::sync_with_stdio(false);
	cin.tie(0);cout.tie(0);
	solve();
	return 0;
}
/*
AC
https://codeforces.com/contest/2052/submission/311474567
*/
```

## 心路历程（WA，TLE，MLE……）