Summary of commonly used STL

Full array

Sort before use

	int a[4];
	for(int i=0;i<4;i++)
		a[i]=i;	
    do
	{
		for(int i=0;i<4;i++)
		cout<<a[i];
		cout<<endl;	
	} 
	while(next_permutation(a,a+4));

unique function

    int a[10] = {1, 1, 1, 1, 2, 3, 4, 4, 9, 9};
    sort(a, a + 10);
    int cnt = unique(a, a + 10) - a;
    for (int i = 0; i < cnt; i++)
        cout << a[i] << " ";
    cout << endl;
    for (int i = 0; i < 10; i++)
        cout << a[i] << " ";
    cout << endl;