Project Euler Problem 125

　単なるブルートフォースなのだが、範囲が違うけど同じ数が出うることと、それを加算してはいけないことに1時間ハマって死にたい。何この凡ミス。

typedef unsigned long long int nat;

vector<nat> gensqsq(nat lim){
	vector<nat> sqsq;
	for(nat i=1;i*i <= lim;++i)sqsq.push_back(i*i);
	return sqsq;
}

bool ispalindromic( nat n ){
	if( n >= 10 && n % 10 == 0 ) return false;
	deque<int> d;
	while( n ){
		d.push_front( n % 10 );
		n /= 10; 
	}
	for( int i=0, j=d.size()-1; i <= j; ++i, --j ){
		if( d[i] != d[j] ) return false;
	}
	return true;
}

nat pe125(){
	set<nat> s;
	nat limit = 100000000;
	nat total = 0;
	
	vector<nat> sq = gensqsq(limit);

	for( nat from = 0; from < sq.size(); ++from){
		nat seqsum = 0;
		for(nat to=from; to < sq.size(); ++to ){
			seqsum += sq[(unsigned int )to];
			if( to == from ) continue;
			if( seqsum >= limit )break;
			if( ispalindromic( seqsum ) )
				s.insert( seqsum );
		}
	}
	for( set<nat>::iterator itr = s.begin(); itr != s.end(); ++itr )
		total += *itr;
	return total;
}