career?id=13729662

    public static void find(int a[]){
        int N = a.length;
        int sum = (N+1)*N / 2;
        int square_sum = N*(N+1)*(2*N+1)/6;

        int sum_a = 0;
        int square_sum_a = 0;
        for(int i = 0;i < a.length;i++){
            sum_a += a[i];
            square_sum_a += Math.pow(a[i],2);
        }
        int m = sum - sum_a;
        int n = square_sum - square_sum_a;
        int p = n/m;

        int x = (p-m)/2;
        int y = (m+p)/2;

        System.out.println("duplicated number is :"+x);
        System.out.println("missing number is :"+y);
    }