title: Find minimum no of swaps required to move all 1's together in a binary array
body: <p>Eg: Array : [0,1,0,1,1,0,0]</p>
  
  <p>Final Array: [0,0,1,1,1,0,0] , So swaps required = 1</p>
  
  <p>i need a O(n) or O(nlogn) solution</p>