這幾天實訓無聊,碰巧藍橋盃賽又要開始報名了,無聊就刷了刷藍橋杯練習系統的題,還都是以前做過的題目。
做到第三題:十六進制轉八進制
沒多想就把第二題的代碼複製過來改了改就提交了,用的是 getchar() 輸入得到字符串中的每一個字符,超時!!!!!
//#include <iostream>
#include <algorithm>
#include <cstdio>
#include <ctime>
#include <cstring>
using namespace std;
//void toEight(long long n) {
// if( n == 0 ) {
// return;
// }
// toEight(n/8);
// printf("%d", n%8);
//}
int main()
{
// int T;
// scanf("%d", &T);
// getchar();
char ch;
// while( T-- ) {
long long num = 0;
double start = clock();
while( ch = getchar() ) {
if( ch == '\n' ) {
break;
}
if( '0' <= ch && ch <= '9' ) {
num = num*16 + (ch-'0');
} else {
switch( ch ) {
case 'A':
num = num*16 + 10;
break;
case 'B':
num = num*16 + 11;
break;
case 'C':
num = num*16 + 12;
break;
case 'D':
num = num*16 + 13;
break;
case 'E':
num = num*16 + 14;
break;
case 'F':
num = num*16 + 15;
break;
}
}
}
printf("%d\n", num);
printf("%f\n", (double)(clock()-start)/CLOCKS_PER_SEC);
// toEight(num);
// putchar('\n');
// }
return 0;
}
改成先用cin輸入得到整個字符串,再對得到的字符串遍歷處理,就不超時通過了!!!!印象中 c語言的getchar()速度不慢啊,而且上面的程序還精簡點,省去了存儲的步驟,按道理來說應該更快的,不懂!!!
#include <iostream>
#include <algorithm>
//#include <cstdio>
#include <ctime>
#include <cstring>
using namespace std;
//void toEight(long long n) {
// if( n == 0 ) {
// return;
// }
// toEight(n/8);
// printf("%d", n%8);
//}
int main()
{
// int T;
// scanf("%d", &T);
// getchar();
char ch[30];
// while( T-- ) {
long long num = 0;
cin >> ch;
// double start = clock();
for( int i=0; i<strlen(ch); ++i ) {
if( '0' <= ch[i] && ch[i] <= '9' ) {
num = num*16 + (ch[i]-'0');
} else {
switch( ch[i] ) {
case 'A':
num = num*16 + 10;
break;
case 'B':
num = num*16 + 11;
break;
case 'C':
num = num*16 + 12;
break;
case 'D':
num = num*16 + 13;
break;
case 'E':
num = num*16 + 14;
break;
case 'F':
num = num*16 + 15;
break;
}
}
}
cout<< num << endl;
// printf("%d\n", num);
// cout << (clock()-start)/CLOCKS_PER_SEC << endl;
// toEight(num);
// putchar('\n');
// }
return 0;
}