POJ 2808 trees outside the gate (Java)

Write the code first, written in Java:

Import java.util.*;
Import java.io.*;
public class Main {
public static void Main (String []args) throws exception{
Scanner input=new Scanner (system.in);
int l=0,m=0,c,b,s=0;
L=input.nextint ();
M=input.nextint ();
int a[]=new int [l+1];
for (int i=0;i<a.length;i++) {
A[i]=1;
}
while (m>0) {
B=input.nextint ();
C=input.nextint ();
for (int i=b;i<=c;i++) {
a[i]=0;
}
m--;
}
for (int i=0;i<a.length;i++) {
if (a[i]==1) {
s++;
}
}
System.out.println (s);
}
}
The idea is to first enter the route length L, define him as an array of length, that is, l=input.nextint (); int a[]=new int [l+1];

Assign each of the arrays to a number of 1. Then accept the input interval length, the corresponding interval of the beginning and end of the middle of the array element assigned to the number 0.

The last count of 1 in the array.

Note: 1. The length of the array is l+1.

        2. If the input interval is 100,200, then the corresponding array's starting and ending positions are a[100] and a[200]. Draw a axis and see how it is.