HDU Computer Transformation1041 题解

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2
3

1
1

找规律的问题，分开0和1的衍生问题就好理解了。

#include <stdio.h>
#include <vector>
#include <string.h>
#include <algorithm>
#include <iostream>
#include <string>
#include <limits.h>
#include <stack>
#include <queue>
#include <set>
#include <map>
using namespace std;

const short MAX_N = 1001;
vector<short> tbl0[MAX_N], tbl1[MAX_N];//inverse saved numbers

void addLargeNum(vector<short> &rs, vector<short> &a, vector<short> &b)
{
	int n = (int)a.size(), m = (int)b.size();
	rs.clear();
	short carry = 0;
	for (int i = 0, j = 0; i < n || j < m || carry; i++, j++)
	{
		short an = i < n ? a[i] : 0;
		short bn = j < m ? b[i] : 0;
		carry += an + bn;
		rs.push_back(carry % 10);
		carry /= 10;
	}
}

void plusOne(vector<short> &a)
{
	if (a.empty()) a.push_back(1);
	else
	{
		int i = 0;
		while (i < (int)a.size() && 9 == a[i]) a[i++] = 0;
		if (i == (int)a.size()) a.push_back(1);
		else a[i]++;
	}
}

void getTbl()
{
	tbl0[0].push_back(0); tbl0[1].push_back(0);
	tbl1[0].push_back(0); tbl1[1].push_back(0);
	
	for (int i = 2; i < MAX_N; i++)
	{
		addLargeNum(tbl0[i], tbl1[i-1], tbl0[i-1]);
		addLargeNum(tbl1[i], tbl0[i-1], tbl1[i-1]);
		if (!(i&1)) plusOne(tbl1[i]);
	}
}

int main()
{
	getTbl();
	int n;
	while (scanf("%d", &n) != EOF)
	{
		vector<short> &a = tbl1[n];
		short m = (short)tbl1[n].size();
		for (short i = m-1; i >= 0; i--)
		{
			printf("%d", a[i]);
		}
		putchar('\n');
	}
	return 0;
}

HDU Computer Transformation1041 题解

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原文地址：http://blog.csdn.net/kenden23/article/details/39997749