UVa 355 The Bases Are Loaded

提醒自己，每次WA都要檢查的事情
1. Bounded Condition ex. 0
2. 變數有效範圍 ex. 是不是超出int的有效範圍，必須改用long long ?
不然很浪費時間 哭哭

這題的另外一個感想就是C++ string實在很難用，
從以前就這樣覺得，這次更加深我的印象。

關鍵測資
5 3 0
16 16 7FFFFFFFFFF
10 10 9999
上面這三個都是有效測資(not illegal)

	#include<iostream>
	#include<algorithm>
	using namespace std;
	inline int CharToDigit(char c)
	{
	if ( isdigit(c) )
	return c - '0';
	return c - 'A' + 10;
	}
	inline char DigitToChar(int n)
	{
	return "0123456789ABCDEF"[n];
	}
	bool checkIllegal(int base1, string& in )
	{
	for (int i = 0; i < in.length(); ++i)
	if ( CharToDigit(in[i]) >= base1 )
	return true;
	return false;
	}
	/* convert string 'in' to int 'value'. */
	long long parseValue( int base1, string& in )
	{
	if ( checkIllegal(base1, in) ) return -1;
	long long value = 0;
	long long curBase = 1;
	for (int i = in.length() - 1; i >= 0; --i)
	{
	value += CharToDigit(in[i]) * curBase;
	curBase *= base1;
	}
	return value;
	}
	/* convert int 'value' to string 'out' */
	string toBase( int base2, long long value )
	{
	if (value == 0) return "0";
	string out;
	while ( value > 0 )
	{
	out += DigitToChar( value % base2 );
	value /= base2;
	}
	reverse(out.begin(), out.end());
	return out;
	}
	int main()
	{
	#ifndef ONLINE_JUDGE
	freopen("355.in", "r", stdin);
	#endif
	int base1, base2;
	string in;
	while ( cin >> base1 >> base2 >> in )
	{
	long long value = parseValue(base1, in);
	if ( value < 0 ) //wrong
	{
	cout << in << " is an illegal base " << base1 << " number\n";
	continue;
	}
	cout << in << " base " << base1 << " = " << toBase(base2, value) << " base " << base2 << "\n";
	}
	return 0;
	}

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