CD142 不用额外变量交换两个整数的值
/* 模拟 */
public class CD142_1
{
public static void solution(int a, int b)
{
a = a ^ b;
b = a ^ b;
a = a ^ b;
System.out.println(a + " " + b);
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int a, b;
a = in.nextInt();
b = in.nextInt();
solution(a, b);
}
}
/* 模拟 */
public class CD142_2
{
public static void solution(int a, int b)
{
a = a + b;
b = a - b;
a = a - b;
System.out.println(a + " " + b);
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int a, b;
a = in.nextInt();
b = in.nextInt();
solution(a, b);
}
}
CD143 不用做任何比较判断找出两个数中较大的数
public class CD143_1
{
public static int solution(int a, int b)
{
int c = a - b;
int sa = sign(a);
int sb = sign(b);
int sc = sign(c);
int difSab = sa ^ sb;
int sameSab = flip(difSab);
int returnA = difSab * sa + sameSab * sc;
int returnB = flip(returnA);
return a * returnA + b * returnB;
}
public static int flip(int n)
{
return n ^ 1;
}
public static int sign(int n)
{
return flip((n >> 31) & 1);
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int a, b;
a = in.nextInt();
b = in.nextInt();
System.out.println(solution(a, b));
}
}
CD144 只用位运算不用算术运算实现整数的加减乘除运算⭐
/*⭐*/
public class CD144_1
{
public static int solutionAdd(int a, int b)
{
int xor = a ^ b;
int and = (a & b) << 1;
if (and == 0) return xor;
return solutionAdd(xor, and);
}
public static int solutionMinus(int a, int b)
{
return solutionAdd(a, solutionAdd(~b, 1));
}
public static int solutionTimes(int a, int b)
{
int ans = 0;
while (b != 0)
{
if ((b & 1) == 1)
ans = solutionAdd(ans, a);
// a <<= 1;
a = solutionAdd(a, a);
b >>>= 1;
}
return ans;
}
public static int div(int a, int b)
{
int x = a < 0 ? solutionAdd(~a, 1) : a;
int y = b < 0 ? solutionAdd(~b, 1) : b;
int res = 0;
for (int i = 31; i >= 0; i = solutionMinus(i, 1))
{
if ((x >> i) >= y)
{
res |= (1 << i);
x = solutionMinus(x, y << i);
}
}
return (a < 0) ^ (b < 0) ? solutionAdd(~res, 1) : res;
}
public static int solutionDiv(int a, int b)
{
if (b == 0) throw new RuntimeException("divisor is 0");
if (a == Integer.MIN_VALUE && b == Integer.MIN_VALUE) return 1;
else if (b == Integer.MIN_VALUE) return 0;
else if (a == Integer.MIN_VALUE)
{
int res = div(solutionAdd(a, 1), b);
return solutionAdd(res, div(solutionMinus(a, solutionTimes(res, b)), b));
}
else
return div(a, b);
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int a, b;
String op;
String[] s = in.nextLine().split(" ");
a = Integer.parseInt(s[0]);
op = s[1];
b = Integer.parseInt(s[2]);
switch (op)
{
case "+":
System.out.println(solutionAdd(a, b));
break;
case "-":
System.out.println(solutionMinus(a, b));
break;
case "*":
System.out.println(solutionTimes(a, b));
break;
case "\\":
System.out.println(solutionDiv(a, b));
break;
}
}
}
CD145 整数的二进制数表达中有多少个 1⭐
public class CD145_1
{
public static int solution(int n)
{
int ans = 0;
for (int i = 31; i >= 0; i--)
if(((n>>>i)&1)==1)
ans++;
return ans;
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = in.nextInt();
System.out.println(solution(n));
}
}
public class CD145_2
{
public static int solution(int n)
{
int res = 0;
while (n != 0)
{
n &= (n - 1);
res++;
}
return res;
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = in.nextInt();
System.out.println(solution(n));
}
}
/*⭐*/
public class CD145_3
{
public static int solution(int n)
{
n = (n & 0x55555555) + ((n >>> 1) & 0x55555555);
n = (n & 0x33333333) + ((n >>> 2) & 0x33333333);
n = (n & 0x0f0f0f0f) + ((n >>> 4) & 0x0f0f0f0f);
n = (n & 0x00ff00ff) + ((n >>> 8) & 0x00ff00ff);
n = (n & 0x0000ffff) + ((n >>> 16) & 0x0000ffff);
return n;
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = in.nextInt();
System.out.println(solution(n));
}
}
CD146 在其他数都出现偶数次的数组中找到出现奇数次的数
public class CD146_1
{
public static int solution(int[] arr)
{
int ans = 0;
for (int num : arr)
ans ^= num;
return ans;
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int[] arr = new int[n];
for (int i = 0; i < n; i++)
arr[i] = in.nextInt();
System.out.println(solution(arr));
}
}
CD147 数组中只出现了一次的数字
public class CD147_1
{
public static void solution(int[] arr)
{
int ans = 0, other = 0;
for (int num : arr)
ans ^= num;
int rightOne = ans & (~ans + 1);
for (int num : arr)
if ((num & rightOne) != 0)
other ^= num;
System.out.println(Math.min(other, ans ^ other) + " " + Math.max(ans ^ other, other));
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n = in.nextInt();
int[] arr = new int[n];
for (int i = 0; i < n; i++)
arr[i] = in.nextInt();
solution(arr);
}
}
CD148 在其他数都出现 k 次的数组中找到只出现一次的数⭐
/*⭐⭐*/
public class CD148_1
{
public static int solution(int[] arr, int k)
{
int[] temp = new int[32];
for (int num : arr)
bin2k(temp, num, k);
return k2bin(temp, k);
}
public static int k2bin(int[] temp, int k)
{
int res = 0, base = 1;
for (int i = 0; i < temp.length; i++)
{
res += base * temp[i];
base *= k;
}
return res;
}
public static void bin2k(int[] temp, int num, int k)
{
int idx = 0;
while (num != 0)
{
temp[idx] = (temp[idx] + num % k) % k;
num /= k;
idx++;
}
}
public static void main(String[] args)
{
Scanner in = new Scanner(System.in);
int n, k;
n = in.nextInt();
k = in.nextInt();
int[] arr = new int[n];
for (int i = 0; i < n; i++)
arr[i] = in.nextInt();
System.out.println(solution(arr, k));
}
}
