数据结构考研学习笔记

计算机考研机试备考（王道）

第二章 暴力求解

1.枚举策略

常见复杂度对应数据量表

例题2.1 abc

#include 
using namespace std;
int main()
{
	int a, b, c;
	for(a=0;a<9;a++)
		for(b=0;b<9;b++)
			for (c = 0; c < 9; c++)
			{
				if ((a * 100 + b * 10 + c + b * 100 + c * 10 + c) == 532)
					cout << a << " " << b << " " << c << endl;
			}
	return 0;
}

例题2.2 反序数

#include 
using namespace std;
int reverse(int number)
{
	int reversenumber = 0;
	while (number != 0)
	{
		reversenumber *= 10;
		reversenumber += number % 10;
		number /= 10;
	}
	return reversenumber;
}
int main()
{
	for (int i = 1000; i < 9999; i++)
		if (i * 9 == reverse(i)) {
			cout << i << endl;
		}
	return 0;
}

例题2.3 对称平方数

#include 
using namespace std;
int Reverse(int number) {
    int reverseNumber = 0;
    while (number != 0) {
        reverseNumber *= 10;
        reverseNumber += number % 10;
        number /= 10;
    }
    return reverseNumber;
}
int main() {
    for (int i = 1; i < 256; i++) {
        if (i * i == Reverse(i * i)) {
            cout << i << endl;
        }
    }
    return 0;
}

2.图形排版

例题2.4 输出梯形

#include 
using namespace std;
int main()
{
	int h;  //梯形行数
	while (cin >> h)
	{
		int row = h;
		int col = h + 2 * (h - 1);  //推导公式得出列数
		for (int i = 0; i < row; ++i)
		{
			for (int j = 0; j < col; ++j)
			{
				if (j < (col - (h + 2 * i)))  //推导公式画出空格数
				{
					cout << " ";
				}
				else
				{
					cout << "*";
				}
			}
			cout << endl;
		}
	}
	return 0;
}

3.日期问题

例题2.5 今年的第几天

#include 
using namespace std;
int dayTable[2][13] = {
    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
bool IsLeapYear(int year) {
    return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
}
int main() {
    int Y, M, D;
    while (cin >> Y >> M >> D) {
        int number = 0;
        int row = IsLeapYear(Y);
        for (int j = 0; j < M; j++) {
            number += dayTable[row][j];
        }
        number += D;
        cout << number << endl;
    }
    return 0;
}

例题2.6 打印日期

#include 
using namespace std;
int dayTable[2][13] = {
    {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31},
    {0, 31, 29, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}
};
bool IsLeapYear(int year) {
    return (year % 4 == 0 && year % 100 != 0) || (year % 400 == 0);
}
int main() {
    int Y, M, D;
    int number = 0;
    while (cin >> Y >> number) {
        M = 0;
        int row = IsLeapYear(Y);
        while (number > dayTable[row][M]) {
            number -= dayTable[row][M];
            M++;
        }
        D = number;
        printf("%04d-%02d-%02d\n", Y, M, D);

    }
    return 0;
}

4.其他模拟

例题2.7 手机键盘