Development with python and related tools-stories and tutorials

  You are given 2 strings   and  �  both containing only lowercase English characters with s containing some  ?  as well. You can swap characters at positions  �  and  �  in the string  �  ( � > � ) any number of times and can also replace any  ?  with any lowercase English character. Can you convert  �  into  �  ? Input Format The first line contains an integer  �  denoting the number of test cases.  The first line of each test case contains an integer  � , the length of the strings. The second line of each test case contains  �  lowercase English characters with some  ? (possibly  0 ) denoting string  � . The third line of each test case contains  �  lowercase English characters denoting string  � . Output Format For each test case, print ' � � � ' (without quotation marks) if it is possible to convert  �  int...

Q.You are given a binary string S of length N. A substring of a binary string is called positive if the number of 1′s present in the substring is strictly greater than the number of 0′s present. Find the number of positive substrings in the given string S Code: (Editorial Solution) # include<bits/stdc++.h> using namespace std; int main() { int tt; cin >> tt; while (tt--) { int n; cin >> n; string s; cin >> s; s = ')' + s; vector< int > pre(n + 1 ), dp(n + 1 ), pos( 2 * n + 1 , - 1 ); for ( int i = 1 ; i <= n; i++) { pre[i] = pre[i - 1 ] + (s[i] == '1' ? 1 : - 1 ); } pos[n] = 0 ; for ( int i = 1 ; i <= n; i++) { int idx = pos[pre[i] + n]; if (s[i] == '1' ) { if (idx == - 1 ) { dp[i] = i; } else { dp[i] = (i - idx - 1 ) + dp[idx]; } } else { if (idx != - 1 ) dp[i] = dp[idx]; } pos[pre[i] + n] = i; } cout << accumulate(dp.begin()...

 I haven't posted for a while, 8 months to be precise. I am practicing DSA nowadays after a lot of soul searching. My plans have taken a left turn very wildly. Hope I achieve my goals.... I do have backup plans so hope that it keeps me in safe position Anyways, I came upon this question in Geeks for Geeks portal. Its a medium-level problem. So I found that ,for this question there were no articles or videos giving the correct solution that works in GFG portal and successfully runs all testcases. There is a GFG video but while its core logic is correct, it doesn't take into account all the different possibilities of solving each testcase so their code doesn't work Here is the link to the GFG video: Video link for problem Problem statement: There are two parallel roads, each containing  N  and  M  buckets, respectively. Each bucket may contain some balls. The balls in first road are given in an array  a  and balls in the second road in an array  b ....