Discussion About Form A New String

#1

This is Discussion thread about Form A New String

#2 
`#include<iostream>
#include<bits/stdc++.h>
using namespace std;

int main() {

cin.tie(NULL);
ios_base::sync_with_stdio(false);

string s,t;
cin>>s>>t;
int ls=s.length();
int lt=t.length();
int count=1;
int j=0;
for(int i=0;i<lt;i++)
{
	int r=j;
	while(s[j]!=t[i])
	{
		j++;
		if(j==ls)
		{
			j=0;
			count++;
		}
		else if(j==r)
		{
			cout<<"-1\n";
			return 0;
		}
	}
	j++;
	if(j==ls)
		{
			j=0;
			count++;
		}
}
cout<<count<<"\n";
return 0;

}`

How to reduce time complexity of this solution? It is exceeding time for a test case.