Problem C. Sum of Factorials


Input file: standard input
Output file: standard output

John von Neumann, b. Dec. 28, 1903, d. Feb. 8, 1957, was a
Hungarian-American mathematician who made important contributions to the
foundations of mathematics, logic, quantum physics, meteorology, science,
computers, and game theory. He was noted for a phenomenal memory and the
speed with which he absorbed ideas and solved problems. In 1925 he received
a B.S. diploma in chemical engineering from Zurich Institute and in 1926 a
Ph.D. in mathematics from the University of Budapest, His Ph.D.
dissertation on set theory was an important contributions to the subject.
At the age of 20, von Neumann proposed a new definition of ordinal numbers
that was universally adopted. While still in his twenties, he made many
contributions in both pure and applied mathematics that established him as
a mathematician of unusual depth. His Mathematical Foundation of Quantum
Mechanics (1932) built a solid framework for the new scientific discipline.
During this time he also proved the mini-max theorem of GAME THEORY. He
gradually expanded his work in game theory, and with coauthor Oskar
Morgenstern he wrote Theory of Games and Economic Behavior (1944).
There are some numbers which can be expressed by the sum of factorials. For
example 9, 9 = 1! + 2! + 3! . Dr. von Neumann was very interested in such
numbers. So, he gives you a number n, and wants you to tell whether or not
the number can be expressed by the sum of some factorials.
Well, it is just a piece of case. For a given n, you will check if there
are some xi, and let n equal to
∑t (上标) i=1(下标) xi! (t≥1, xi≥0, xi = xj <==> i = j)
即  ∑    xi! (t≥1, xi≥0, xi = xj <==> i = j)
If the answer is yes, say "YES"; otherwise, print out

You will get a non-negative integer n (n≤1,000,000) from input file.

For the n in the input file, you should print exactly one word ("YES" or
"NO") in a single line. No extra spaces are allowed.

Sample input and output
Standard input                      standard output
9                                   YES
2                                   YES

// Since the max input value is 1000000
#define MAX_NUM 10
int _tmain(int argc, _TCHAR* argv[])
 unsigned long values[MAX_NUM];
 int i = 1;
 values[i – 1] = 1;
 for (i = 2; i <= MAX_NUM; ++i)
  values[i – 1] = values[i – 2] * i;
 unsigned long input = 0;
 cin >> input;
 while (input > 0)
  unsigned long b = 0;
  int start = MAX_NUM – 1;
  int i;
  for (i = start; i >= 0; –i)
   b += values[i];
   if (input < b)
    b -= values[start];
   else if (input == b)
    cout << "YES" << endl;
  if (i < 0)
   cout << "NO" << endl;
  cin >> input;
 return 0;

整理 — 深入剖析数组与指针


int a[3] = {0, 0, 0};
int *pa = a;
pa[1] = 1; //语句1
a[1] = 2; //语句2
mov eax, dword ptr[pa]
mov dword ptr [eax + 4], 1 // 语句1
mov dword ptr [ebp-18h], 2 // 语句2
pa++; // 编译通过
a++; // 编译错误
void func(int a[])
int i = sizeof(a);