Algorithm
You are given a string s consisting only of characters 0 and 1. A substring [l, r] of s is a string slsl + 1sl + 2... sr, and its length equals to r - l + 1. A substring is called balanced if the number of zeroes (0) equals to the number of ones in this substring.
You have to determine the length of the longest balanced substring of s.
The first line contains n (1 ≤ n ≤ 100000) — the number of characters in s.
The second line contains a string s consisting of exactly n characters. Only characters 0 and 1 can appear in s.
If there is no non-empty balanced substring in s, print 0. Otherwise, print the length of the longest balanced substring.
8
11010111
4
3
111
0
In the first example you can choose the substring [3, 6]. It is balanced, and its length is 4. Choosing the substring [2, 5] is also possible.
In the second example it's impossible to find a non-empty balanced substring.
Code Examples
#1 Code Example with C++ Programming
Code -
C++ Programming
#include<iostream>
#include<string>
using namespace std;
int fun(string s, int n){
int a = 0, b = 0;
if(n==1){
cout<<-1<<" ";
cout<<-1<<endl;
return 0;
}
for(int r = n-1; r > 0; r--){
for(int l = 0; l < r; l++){
for(int i = l; i <= r; i++){
if(s[i] == 'a'){
a++;
}
else{
b++;
}
}
if(a == b){
cout<<(l+1)<<" ";
cout<<(r+1)<<endl;
return 0;
}
a = 0; b = 0;
}
}
cout<<-1<<" ";
cout<<-1<<endl;
return 0;
}
int main(){
int t, n;
cin>>t;
string s;
for(int j = 0; j < t; j++){
cin>>n;
cin>>s;
fun(s, n);
}
}Input
11010111
Output
Demonstration
Codeforcess Solution 873-B B. Balanced Substring ,C++, Java, Js and Python ,873-B,Codeforcess Solution