《Cracking the Coding Interview》——第5章：位操作——题目1

2014-03-19 05:45

题目：给定两个数M和N，将N按照二进制位，覆盖到M的特定段位中去。

解法：位操作，请看代码。

代码：

 // 5.1 Insert one number into the certain bit segment of another number.
 #include <cstdio>
 using namespace std;

 void printBinary(unsigned num)
 {
     unsigned bit =  << ;

     do {
         putchar('' + !!(num & bit));
         bit >>= ;
     } while (bit);
 }

 unsigned insertBits(unsigned n, unsigned m, int ll, int rr)
 {
     return (n >> (rr + ) << (rr + )) + (m << ll) + (n - (n >> ll << ll));
 }

 int main()
 {
     unsigned n, m;
     unsigned res;
     int low, high;

     while (scanf("%u%u", &n, &m) == ) {
         scanf("%d%d", &low, &high);
         res = insertBits(n, m, low, high);
         printBinary(n);
         putchar('\n');
         printBinary(m);
         putchar('\n');
         printBinary(res);
         putchar('\n');
     }

     return ;
 }