Climbing Stairs

public int climbStairs(int n) {
        // Start typing your Java solution below
        // DO NOT write main() function
        if(n<=0) return 0;
  
        int array[] = new int[n+1];
        array[1]=1;
        array[0]=1;
        for(int i=2;i<=n;i++){
            array[i]=array[i-1]+array[i-2];
        }
       
        return array[n];
    }