7-1 Simplified insertion sort
#include<stdio.h>
int main()
{
int n,a[1001],x;
scanf("%d", & amp;n);
for(register int i=0;i<n;i + + )
{
scanf("%d", & amp;a[i]);
}
scanf("%d", & amp;x);
a[n]=x;//Put x at the end of the array
for(register int i=n;i>=1;i--)//Comparison starts from the last bit of the array in a way similar to bubble sorting
{
if(a[i]<a[i-1])//If it is smaller, move forward
{
int t;
t=a[i-1];
a[i-1]=a[i];
a[i]=t;
}
else
{
break;
}
}
for(register int i=0;i<=n;i + + )
{
printf("%d ",a[i]);
}
return 0;
}
7-2 Spiral Square
#include <stdio.h>
int main() {
int n, num = 1, pos, a[101][101]; //pos is the number of circles
scanf("%d", & amp;n);
if (n % 2 == 1) {
pos = n / 2 + 1;//if n is an odd number
} else {
pos = n / 2;//n is an even number
}
for (register int i = 1; i <= pos; i + + ){ //fill in circles
//horizontal
for (register int j = i; j <= (n - i + 1); j + + ) {
a[i][j] = num;
num + + ;
}
num--;//Avoid duplication of corners
//right side vertical
for (register int j = i; j <= (n - i + 1); j + + ) {
a[j][n - i + 1] = num;
num + + ;
}
num--;
//lower side
for (register int j = (n - i + 1); j >= i; j--) {
a[n - i + 1][j] = num;
num + + ;
}
num--;
//left vertical
for (register int j = (n - i + 1); j > i; j--) {
a[j][i] = num;
num + + ;
}
}
//generate first and then output
for (register int i = 1; i <= n; i + + ) {
for (register int j = 1; j <= n; j + + ) {
printf("=", a[i][j]);
}
printf("\
");
}
return 0;
}
7-3 Matrix A times B
I haven’t passed my own code, source of ideas: pta7-3 matrix A multiplied by B
The core part is basically copied. It is recommended to learn matrix multiplication first.
#include<stdio.h>
int main()
{
int a[101][101],b[101][101],ar,ac,br,bc,ans;//r is the row and c is the column
scanf("%d %d", & amp;ar, & amp;ac);
for(register int i=1;i<=ar;i + + )
{
for(register int j=1;j<=ac;j + + )
{
scanf("%d", & amp;a[i][j]);
}
}
scanf("%d %d", & amp;br, & amp;bc);
for(register int i=1;i<=br;i + + )
{
for(register int j=1;j<=bc;j + + )
{
scanf("%d", & amp;b[i][j]);
}
}
if(ac!=br)
{
printf("Error: %d != %d",ac,br);
return 0;
}
printf("%d %d\
",ar,bc);
for(register int i=1;i<=ar;i + + )
{
for(register int j=1;j<=bc;j + + )
{
ans=0;
for(register int k=1;k<=ac;k + + )
{
ans=ans + a[i][k]*b[k][j];
}
printf("%d",ans);
if(j!=bc)
{
printf(" ");
}
}
printf("\
");
}
return 0;
}
7-5 Go together for an autumn outing
#include<stdio.h>
int main()
{
int n,a[1001];
scanf("%d", & amp;n);
for(register int i=1;i<=n;i + + )
{
scanf("%d", & amp;a[i]);
}
for(register int i=1;i<=n/2;i + + )
{
printf("%d %d\
",a[i],a[n-i + 1]);//Output the first and last elements of the array
}
return 0;
}
7-6 Deletion of array elements
#include<stdio.h>
int main()
{
int n,k,a[1001];
scanf("%d", & amp;n);
for(register int i=0;i<n;i + + )
{
scanf("%d", & amp;a[i]);
}
scanf("%d", & amp;k);
for(register int i=1;i<=k;i + + )
{
int t;
scanf("%d", & amp;t);
for(register int j=t-1;j<n;j + + )//Starting from the deleted bit, move each item forward
{
a[j]=a[j + 1];
}
}
for(register int i=0;i<(n-k-1);i + + )//The number of elements in the array has changed after deletion
{
printf("%d ",a[i]);
}
printf("%d\
",a[n-k-1]);//In order to comply with the format
return 0;
}
7-7 supermarket decals
#include<stdio.h>
int main()
{
int n,a[1001];
scanf("%d", & amp;n);
for(register int i=1;i<=n;i + + )
{
scanf("%d", & amp;a[i]);
}
for(register int i=1;i<=n;i + + )//Sort, bubble sort is used here
{
for(register int j=i;j<=(n-1);j + + )
{
if(a[j]>a[j + 1])
{
int t;
t=a[j];
a[j]=a[j + 1];
a[j + 1]=t;
}
}
}
int pos=1,ans=0;
//Used to check sorting results
/*for(register int i=1;i<=n;i + + )
{
printf("%d ",a[i]);
}*/
for(register int i=2;i<=n;i + + )
{
if(a[i]==(a[i-1] + 1))//Judge continuity
{
pos + + ;
}
if(pos==3)//If there are three consecutive numbers
{
ans + + ;
pos=1;
}
}
printf("%d",ans);
return 0;
}
7-8 Square matrix circular shift to the right
#include<stdio.h>
int main()
{
int n,m,a[101][101],b[101][101];
scanf("%d %d", & amp;m, & amp;n);
if(m>n)//It is periodic, moving n distances is the same as the original
{
m=m%n;
}
for(register int i=1;i<=n;i + + )
{
for(register int j=1;j<=n;j + + )
{
scanf("%d", & amp;a[i][j]);
b[i][j]=a[i][j];//Copy the original copy
}
}
for(register int i=1;i<=n;i + + )
{
for(register int j=1;j<=n;j + + )
{
if((j + m)<=n)//If the array range will not be exceeded during the right shift
{
a[i][j + m]=b[i][j];
}
else//If it exceeds, fold off the excess and put it at the beginning, that is, subtract n
{
a[i][j + m-n]=b[i][j];
}
}
}
for(register int i=1;i<=n;i + + )
{
for(register int j=1;j<=n;j + + )
{
printf("%d ",a[i][j]);
}
printf("\
");
}
return 0;
}
7-9 Print Yang Hui triangle
Classic questions
#include<stdio.h>
int main()
{
int n,a[101][101];
scanf("%d", & amp;n);
for(register int i=1;i<=n;i + + )//Initialization, the numbers on both sides are one
{
a[i][1]=1;
a[i][i]=1;
}
for(register int i=3;i<=n;i + + )
{
for(register int j=2;j<=i;j + + )
{
a[i][j]=a[i-1][j-1] + a[i-1][j];//This is the law of Yang Hui’s triangle
}
}
for(register int i=1;i<=n;i + + )
{
for(register int j=1;j<=i;j + + )
{
if(j==1)//In order to comply with the format
{
for(register int k=(n-i);k>=1;k--)
{
printf(" ");
}
}
printf("M",a[i][j]);//Each number occupies four digits
}
printf("\
");
}
return 0;
}
7-10 divided into two columns
#include<stdio.h>
struct ss
{
int num,pos;//num is the student number, pos records odd and even numbers
}a[1001];
int main()
{
int n;
scanf("%d", & amp;n);
for(register int i=1;i<=n;i + + )
{
scanf("%d", & amp;a[i].num);
if(i%2==1)
{
a[i].pos=1;
}
else
{
a[i].pos=0;
}
}
//printf("%d",a[1].num);
for(register int i=1;i<=n;i + + )//first column
{
if(a[i].pos==1)
{
if(i==1)
{
printf("%d",a[i].num);
continue;
}
printf(" ");//For formatting
printf("%d",a[i].num);
}
}
//printf("\
%d",a[2].num);
printf("\
");
for(register int i=1;i<=n;i + + )//second column
{
if(a[i].pos==0)
{
if(i==2)
{
printf("%d",a[i].num);
continue;
}
printf(" %d",a[i].num);//For format
}
}
printf("\
");//If the number of people is 1, the point must have three lines to pass?
return 0;
}
7-11 Left-pad
#include<stdio.h>
#include<string.h>
int main()
{
int n;
char c,s[100001];
scanf("%d %c", & amp;n, & amp;c);
getchar();
//Be careful to remove the carriage return at the end of the last input, that is, a single character cannot be connected to my string (my understanding)
gets(s);
//puts(s);//Used during debugging
if(n<=strlen(s))//The number of digits to be retained is less than the string length
{
for(register int i=(strlen(s)-n);i<strlen(s);i + + )
{
printf("%c",s[i]);
}
return 0; //End program
}
for(register int i=1;i<=(n-strlen(s));i + + )
{
printf("%c",c);//Insufficient completion
}
for(register int i=0;i<strlen(s);i + + )
{
printf("%c",s[i]);output as usual
}
return 0;
}
7-12 Matrix operations
#include<stdio.h>
int main()
{
int n,a[101][101],ans=0;
scanf("%d", & amp;n);
for(register int i=1;i<=n;i + + )
{
for(register int j=1;j<=n;j + + )
{
scanf("%d", & amp;a[i][j]);
if(i==n||j==n)//Do not add the last column and row
{
continue;
}
ans + =a[i][j];//Accumulate while inputting
}
}
for(register int i=2,j=(n-1);i<=(n-1),j>=2;i + + ,j--)
{
ans-=a[i][j];//Subtract the ones on the sub-diagonal, be careful not to subtract too much on the two corners
}
printf("%d",ans);
return 0;
}
7-13 Array circular shift left
#include<stdio.h>
int main()
{
int n,m,a[1001],b[1001];
scanf("%d %d", & amp;n, & amp;m);
if(m>n)//Moving n has the same effect as no movement
{
m=m%n;
}
for(register int i=0;i<n;i + + )
{
scanf("%d", & amp;a[i]);
b[i]=a[i];//Copy the original copy
}
for(register int i=0;i<n;i + + )
{
if((i-m)<0)//Determine whether the array range is exceeded
{
a[i-m + n]=b[i];
}
else//If not exceeded, move directly
{
a[i-m]=b[i];
}
}
printf("%d",a[0]);//For formatting
for(register int i=1;i<n;i + + )
{
printf(" %d",a[i]);//For format
}
return 0;
}