error with operators in vector

[Teerlinc]

Hello, I am getting an error with all of the operators in my program... I would understand if I had not included <string> or <vector>, but aren't these operators defined in these files? Can someone help me figure out why these operators are not defined in my program?

I am using Visual C++ and the general error I am getting is:

error C2784: 'std::reverse_iterator<_RanIt> std::operator +(_Diff,const std::reverse_iterator<_RanIt> &)' : could not deduce template argument for 'const std::reverse_iterator<_RanIt> &' from 'unsigned int'

And here is my code:

#include <vector>
#include <cstdio>
#include <iostream>
#include <string>
using namespace std;
 
// Function finds longest strictly increasing subsequence. 
// O(n log k) algorithm. 
void find_lis(vector<string> &a, vector<string> &b)
{
	vector<string> p(a.size());
	int u, v;
 
	if (a.empty()) 
		return;
 
	b.push_back(0);
 
	for (size_t i = 1; i < a.size(); i++) 
        {
                // If next element a[i] is greater than last element of current longest subsequence a[b.back()], just push it at back of "b" and continue
		if (a[b.back()] < a[i]) 
                {
			p[i] = b.back();
			b.push_back(i);
			continue;
		}
 
                // Binary search to find the smallest element referenced by b which is just bigger than a[i]
                // Note : Binary search is performed on b (and not a). Size of b is always <=k and hence contributes O(log k) to complexity.    
		for (u = 0, v = b.size()-1; u < v;) 
        {
			int c = (u + v) / 2;
			if (a[b[c]] < a[i]) u=c+1; 
			else v=c;
		}
 
                // Update b if new value is smaller then previously referenced value 
		if (a[i] < a[b[u]]) 
        {
			if (u > 0) p[i] = b[u-1];
			b[u] = i;
		}	
	}
 
	for (u = b.size(), v = b.back(); u--; v = p[v]) b[u] = v;
}
 
// test

int main()
{
	string series;

	cout << "Please enter a series of letters: " << endl;
	cin >> series;

	vector<string> seq(series, series+sizeof(series)/sizeof(series[0])); // seq : Input Vector
	vector<string> lis;                              // lis : Vector containing indexes of longest subsequence 
        find_lis(seq, lis);
 
        //Printing actual output 
	for (size_t i = 0; i < lis.size(); i++)
		printf("%d ", seq[lis[i]]);
        printf("\n");    
 
	system ("pause");
	return 0;
}

[Stewbond]

when you do things like this:

int i; 
vector<string> b;
b.push_back(i)

You are causing a problem because you are trying to stick an int into a string. If you are trying to put a numeral in there, then cast it to a char if it is a single digit like: b.push_back(char(i+'0'));. If not, then use a stringstream object like:

int i;
stringstream ss(i);
vector<string> b;
b.push_back(ss.str())

Likewise things like:

vector<string> p;
p.push_back("Hello")l
int i = p[0];

That's the same problem but reversed.

I think stringstream is your friend here.

Another thing that I'd recommend is using iterators. Instead of doing this:

int i;
vector<string> b;
for (i = 0; i < b.size(); i++)
    cout << b[i];

Try this:

vector<string>::iterator iter;
vector<string> b;
for (iter = b.begin(); iter < b.end(); iter++)
    cout << *iter;