The first few questions are too simple to skip.
Question F: String inversion
Topic Description
Little C likes to write words backwards. Now give you a line of text in lowercase C. Can you reverse every word and output them?
input
The input contains multiple sets of test samples. The first action is an integer T, representing the number of test cases, followed by T test cases.
Each test sample takes up one line and contains more than one word. A line has a maximum of 1000 characters.
Each test sample takes up one line and contains more than one word. A line has a maximum of 1000 characters.
output
For each test case, you should output the converted text.
sample input
3 olleh !dlrow I ekil .bulcmca I evol .mca
sample output
hello world!
I like acmclub.
I love acm.
The first submission shows compilation errors, what ignores the return value of the function (black question mark......)
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 void change(char str[]) 8 { 9 int i,j; 10 j=0; 11 char string[50]; 12 if(strlen(str)==1) 13 { 14 printf("%s",str); 15 return ; 16 } 17 for(i=strlen(str)-1;i>=0;i--) 18 { 19 string[j++]=str[i]; 20 } 21 string[j++]=0; 22 printf("%s",string); 23 return ; 24 } 25 26 int main() 27 { 28 int n; 29 scanf("%d",&n); 30 getchar(); 31 while(n--) 32 { 33 char str[1000]; 34 gets(str); 35 int len=strlen(str); 36 str[len]=' '; 37 len++; 38 str[len]=0; 39 char tem[50]; 40 int j=0; 41 for(int i=0;i<len;i++) 42 { 43 if(str[i]!=' ') 44 { 45 tem[j++]=str[i]; 46 } 47 else if(str[i]==' '&&str[i-1]!=' ') 48 { 49 tem[j++]=0; 50 change(tem); 51 j=0; 52 memset(tem,0,sizeof(tem)); 53 if(i!=len-1) printf(" "); 54 } 55 else 56 printf(" "); 57 } 58 printf("\n"); 59 } 60 return 0; 61 } 62 /************************************************************** 63 Problem: 1095 64 User: 201820222 65 Language: C++ 66 Result: Compilation error 67 ****************************************************************/
The second time you delete a return from the change, you compile it (again black question mark), but it shows a running error.
Runtime errors, illegal memory access, array crossing, pointer drift, calling disabled system functions, etc.
The guess array is smaller.
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 void change(char str[]) 8 { 9 int i,j; 10 j=0; 11 char string[50]; 12 for(i=strlen(str)-1;i>=0;i--) 13 { 14 string[j++]=str[i]; 15 } 16 string[j++]=0; 17 printf("%s",string); 18 return ; 19 } 20 21 int main() 22 { 23 int n; 24 scanf("%d",&n); 25 getchar(); 26 while(n--) 27 { 28 char str[1000]; 29 gets(str); 30 int len=strlen(str); 31 str[len]=' '; 32 len++; 33 str[len]=0; 34 char tem[50]; 35 int j=0; 36 for(int i=0;i<len;i++) 37 { 38 if(str[i]!=' ') 39 { 40 tem[j++]=str[i]; 41 } 42 else if(str[i]==' '&&str[i-1]!=' ') 43 { 44 tem[j++]=0; 45 change(tem); 46 j=0; 47 memset(tem,0,sizeof(tem)); 48 if(i!=len-1) printf(" "); 49 } 50 else 51 printf(" "); 52 } 53 printf("\n"); 54 } 55 return 0; 56 } 57 /************************************************************** 58 Problem: 1095 59 User: 201820222 60 Language: C++ 61 Result: Running error 62 ****************************************************************/
The third time, perfect.
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 void change(char str[]) 8 { 9 int i,j; 10 j=0; 11 char string[1001]; 12 for(i=strlen(str)-1;i>=0;i--) 13 { 14 string[j++]=str[i]; 15 } 16 string[j++]=0; 17 printf("%s",string); 18 return ; 19 } 20 21 int main() 22 { 23 int n; 24 scanf("%d",&n); 25 getchar(); 26 while(n--) 27 { 28 char str[1001]; 29 gets(str); 30 int len=strlen(str); 31 str[len]=' '; 32 len++; 33 str[len]=0; 34 char tem[1001]; 35 int j=0; 36 for(int i=0;i<len;i++) 37 { 38 if(str[i]!=' ') 39 { 40 tem[j++]=str[i]; 41 } 42 else if(str[i]==' '&&str[i-1]!=' ') 43 { 44 tem[j++]=0; 45 change(tem); 46 j=0; 47 memset(tem,0,sizeof(tem)); 48 if(i!=len-1) printf(" "); 49 } 50 else 51 printf(" "); 52 } 53 printf("\n"); 54 } 55 return 0; 56 } 57 /************************************************************** 58 Problem: 1095 59 User: 201820222 60 Language: C++ 61 Result: Correct 62 Time:1 ms 63 Memory:1120 kb 64 ****************************************************************/
Although this problem is full of twists and turns, it is very happy that the memory consumption is the shortest.
Question H: easy
Topic Description
Input a string and output the longest palindrome substring length of the string
Substring: String fragments that appear continuously in the original string.
(Tencent Interview Question)
Substring: String fragments that appear continuously in the original string.
(Tencent Interview Question)
input
Only one line, containing a string, not more than 100 lengths
output
Output an integer, the length of the longest palindrome substring
sample input
1abcba2
sample output
5
Direct Parity, Violent Solution
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 int main() 8 { 9 char str[100]; 10 gets(str); 11 int max=0; 12 for(int i=1;i<strlen(str);i++) 13 { 14 int m=1; 15 for(int j=1;;j++) 16 { 17 if(i-j<0||i+j>strlen(str)) 18 break; 19 else if(str[i-j]==str[i+j]) 20 m+=2; 21 else 22 break; 23 } 24 if(m>max) 25 max=m; 26 } 27 for(int i=1;i<strlen(str)-1;i++) 28 { 29 if(str[i]!=str[i+1]) 30 continue; 31 int m=2; 32 for(int j=1;;j++) 33 { 34 if(i-j<0||i+1+j>strlen(str)) 35 break; 36 else if(str[i-j]==str[i+1+j]) 37 m+=2; 38 else 39 break; 40 } 41 if(m>max) 42 max=m; 43 } 44 printf("%d\n",max); 45 return 0; 46 }
You can also set i, j, traverse from both ends, use reverse, exchange strings between I and j, store them in a temporary array, and then see if the temporary array and the original string are equal, when the same j-i+1 should be the largest.
Question I: Longest Common Subsequence
Topic Description
Give you a sequence X and another sequence Z. When all the elements in Z exist in X and the subscript order in X is strictly incremental, then Z is called a subsequence of X.
For example, Z=<a, b, f, c> is a subsequence of sequence X=<a, b, c, f, b, c>, and the subscript sequence of elements in Z in X is <1, 2, 4, 6>.
Here are two sequences X and Y. What is the length of their longest common subsequence?
For example, Z=<a, b, f, c> is a subsequence of sequence X=<a, b, c, f, b, c>, and the subscript sequence of elements in Z in X is <1, 2, 4, 6>.
Here are two sequences X and Y. What is the length of their longest common subsequence?
input
The input contains multiple sets of test data. Each set of inputs takes up one line and is two strings separated by several spaces. The length of each string does not exceed 100.
output
For each set of inputs, the length of the longest common subsequence of two strings is output.
sample input
abcfbc abfcab
programming contest
abcd mnp
sample output
4 2 0
This classic DP, I've seen it before, but I've almost forgotten it. Let's keep it. When reviewing DP next week, I'll watch it.
Question J: Limits of string statistics
Topic Description
Give a string, consisting of only uppercase and lowercase letters, in which the uppercase letters are picked out in the original order to form a new string and output the string.
input
One line, string. 1=<Length<=10000000
output
A string of pure capitals
sample input
AAaaBBbb
sample output
AABB
That's right, but the details aren't ready. Let's go ahead and look at it. Ouch.
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 int main() 8 { 9 char c;10 c=getchar(); 11 while(c!='\n') 12 { 13 if(c>='A'&&c<='Z') 14 printf("%c",c); 15 c=getchar(); 16 } 17 printf("\n"); 18 return 0; 19 } 20 /************************************************************** 21 Problem: 4388 22 User: 201820222 23 Language: C++ 24 Result: Overtime 25 ****************************************************************/
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 int main() 8 { 9 char c; 10 while(~scanf("%c",&c)) 11 { 12 if(c>='A'&&c<='Z') 13 printf("%c",c); 14 } 15 printf("\n"); 16 return 0; 17 } 18 /************************************************************** 19 Problem: 4388 20 User: 201820222 21 Language: C++ 22 Result: Overtime 23 ****************************************************************/
The most interesting thing is the following, the same code, different results...
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 int main() 8 { 9 char ch; 10 while((ch=getchar())!=EOF&&ch!='\n') 11 { 12 if(ch>='A'&&ch<='Z') 13 printf("%c",ch); 14 } 15 printf("\n"); 16 return 0; 17 } 18 /************************************************************** 19 Problem: 4388 20 User: 201820222 21 Language: C++ 22 Result: Compilation error 23 ****************************************************************/
1 #include <stdio.h> 2 #include <string.h> 3 #include <algorithm> 4 5 using namespace std; 6 7 int main() 8 { 9 char ch; 10 while((ch=getchar())!=EOF&&ch!='\n') 11 { 12 if(ch>='A'&&ch<='Z') 13 printf("%c",ch); 14 } 15 printf("\n"); 16 return 0; 17 } 18 /************************************************************** 19 Problem: 4388 20 User: 201820222 21 Language: C++ 22 Result: Correct 23 Time:593 ms 24 Memory:1120 kb 25 ****************************************************************/