a_127_StockSpan.java

import java.util.Stack;

public class a_127_StockSpan {
    public static void stockSpan(int stock[], int span[]) {
        Stack<Integer> s = new Stack<>() ;
        span[0] = 1 ;
        s.push(0);

        for(int i=1; i<stock.length ; i++){
            int currPrice = stock[i] ;
            while( !s.isEmpty()  && currPrice > stock[s.peek()]){
                s.pop() ;
            }

            if(s.isEmpty()){
                span[i] = i+1 ;
            }
            else{
                int prevHigh = s.peek() ;
                span[i] = i - prevHigh ;
            }

             s.push(i) ;
        }

    }

    public static void main(String[] args) {
        int stock[] = {100, 80, 60, 70, 60, 85, 100} ;
        int span[] = new int[stock.length] ;

        stockSpan(stock, span);

        for(int i=0; i<span.length ; i++){
            System.out.print(span[i] +" ");
        }

    }
}