一些 Leetcode 里面经常用到的函数模板

类型定义简化

using namespace std;
typedef long long LL;
typedef vector<int> VI;

#define REP(i,s,t) for(int i=(s);i<(t);i++)
#define FILL(x,v) memset(x,v,sizeof(x))
#define EACH(i, c) for (__typeof((c).begin()) i = (c).begin(), i##_end = (c).end(); i != i##_end; ++i)
#define eprintf(...) fprintf(stderr, __VA_ARGS__)

const int INF = (int)1E9;
#define MAXN 10005

一些常用的模板函数

From Leetcode 用户natsugiri

template <class T>
inline void amin(T &x, const T &y) {
  if (y < x) x = y;
}

template <class T>
inline void amax(T &x, const T &y) {
  if (x < y) x = y;
}

template <class Iter>
void rprintf(const char *fmt, Iter begin, Iter end) {
  for (bool sp = 0; begin != end; ++begin) {
    if (sp)
      putchar(' ');
    else
      sp = true;
    printf(fmt, *begin);
  }
  putchar('\n');
}

如果你并不知道你需要申请的 int 类型在机器上的空间大小的话, 就需要使用 sizeof 函数来判断.

int *c = (int*)malloc(100 * sizeof(int))

Stack 的应用, 在递归的时候就会使用到这种情况.

Programming Practice:

The interviewer says: "Write for me a program in C++ that takes as input a list of names, and prints out each name that appears in the list multiple times."

在使用 Linked List 的时候,不要使用下面这种方式, 这样会导致内存泄露

Node* temp = new Node;
temp = n;

在使用 Linked List 的时候, 应该检查当前结点, 不要使用下一个结点作为检查

while(temp->next != nullptr) {
  temp = temp->next;
}
这种写的办法, 如果Linked list 是空的话, 这样代码会崩溃. 应该写成:

while(temp != nullptr) {

}

如何测试你的代码的运行时间:

seq 20000 > | input : time ./a.out < input

Computer sciencist Abstraction

• Don't think about everything at once.
• Don't worry about irrelevant low-level details when thinking about a high-level idea.
• However, this doesn't mean you can ignore the low-level details -- these may have a large impact on performance, and can sometimes cause unexpected behavior.
• It often helps to know as much of technology Stack as possible ...