Minimum toggles to partition a binary array so that it has first 0s then 1s in C++

Problem statement

Given an array of n integers containing only 0 and 1. Find the minimum toggles (switch from 0 to 1 or vice-versa) required such the array the array become partitioned, i.e., it has first 0s then 1s.

Example

If arr[] = {1, 0, 0, 1, 1, 1, 0} then 2 toggle is required i.e. toggle first one and last zero.

Algorithm

• If we observe the question, then we will find that there will definitely exist a point from 0 to n-1 where all elements left to that point should contains all 0’s and right to point should contains all 1’s
• Those indices which don’t obey this law will have to be removed. The idea is to count all 0s from left to right.

Example

 Live Demo

#include <bits/stdc++.h>
using namespace std;
int getMinToggles(int *arr, int n) {
   int zeroCnt[n + 1] = {0};
   for (int i = 1; i <= n; ++i) {
      if (arr[i - 1] == 0) {
         zeroCnt[i] = zeroCnt[i - 1] + 1;
      } else {
         zeroCnt[i] = zeroCnt[i - 1];
      }
   }
   int result = n;
   for (int i = 1; i <= n; ++i) {
      result = min(result, i - zeroCnt[i] + zeroCnt[n] - zeroCnt[i]);
   }
   return result;
}
int main() {
   int arr[] = {1, 0, 0, 1, 1, 1, 0};
   int n = sizeof(arr) / sizeof(arr[0]);
   cout << "Minimum toggles = " << getMinToggles(arr, n) << endl;
   return 0;
}

When you compile and execute above program. It generates following output −

Output

Minimum toggles = 2

Narendra Kumar

Published on 20-Dec-2019 10:10:05

• Related Questions & Answers
• XOR counts of 0s and 1s in binary representation in C++
• Check if a string has m consecutive 1s or 0s in Python
• Print n 0s and m 1s such that no two 0s and no three 1s are together in C Program
• Check if it is possible to rearrange a binary string with alternate 0s and 1s in Python
• Minimum flips in two binary arrays so that their XOR is equal to another array in C++.
• Minimum flips to make all 1s in left and 0s in right in C++
• Check if the binary representation of a number has equal number of 0s and 1s in blocks in Python
• Count all 0s which are blocked by 1s in binary matrix in C++
• Add minimum number to an array so that the sum becomes even in C++?
• Find the minimum value to be added so that array becomes balanced in C++
• Find minimum value to assign all array elements so that array product becomes greater in C++
• Check if a binary string has a 0 between 1s or not in C++
• Program to find number m such that it has n number of 0s at end in Python
• Add minimum number to an array so that the sum becomes even in C programming
• Count permutations that are first decreasing then increasing in C++