习题8-7(uva-11925)

#include <iostream>
#include <istream>
#include <sstream>
#include <vector>
#include <stack>
#include <list>
#include <map>
#include <set>
#include <deque>
#include <queue>
#include <cstring>
#include <unordered_map>
#include <unordered_set>
#include <algorithm>
#include <numeric>
#include <chrono>
#include <ctime>
#include <cmath>
#include <cctype>
#include <string>
#include <cstdio>
#include <iomanip>


#include <thread>
#include <mutex>
#include <condition_variable>
#include <functional>
#include <iterator>
using namespace std;
const int maxn = 512,maxm = 1e6 + 7;
int arr[maxn], cnt, ans[maxm], rcnt;

void DoSwap(int a)
{
    
    
	int next = (a + 1 + cnt) % cnt;
	swap(arr[a], arr[next]);
	ans[rcnt++] = 1;
}
void DoPushback()
{
    
    
	ans[rcnt++] = 2;
}

bool IsOk(int index) {
    
    
	int last = (index - 1 + cnt) % cnt,val = 1;
	if (arr[index] != 1) return false;
	while (index != last) {
    
    
		if (arr[index] != val++) return false;
		index = (index + 1) % cnt;
	}
	return true;
}
void GetResult()
{
    
    
	int cur = 0;
	while (!IsOk(cur)) {
    
    
		int next = (cur + 1) % cnt;
		if (arr[cur] != cnt && arr[cur] > arr[next] ) DoSwap(cur);
		if (IsOk(cur)) return;
		DoPushback();
		cur = (cur - 1 + cnt) % cnt;
	}
}
int main()
{
    
    
	while (cin >> cnt && cnt) {
    
    
		rcnt = 0;
		for (int i = 0; i < cnt; i++) cin >> arr[i];
		GetResult();
		for (int i = rcnt - 1; i >= 0; i--)
			cout << ans[i];
		cout << endl;
	}
	return 0;
}