Here is the program:
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
char *stack;
int stackindex = 0;
int push(char in){
if (stack==NULL) {
stack = (char *) malloc (sizeof(char));
}
else {
stack = (char *) realloc(stack, sizeof(char)* ++stackindex);
}
stack[stackindex] = in;
return 1;
}
char pop(){
return stack[stackindex--];
}
void show() {
for (int i=stackindex; i>=0;i--) {
printf("%c", pop());
}
}
int main(int argc, char**argv) {
for (int i = 1; i < argc; i++) {
int k = strlen(argv[i]);
int j;
for (int j = 0; j < k ; j++) {
char in = argv [i] [j];
push( in );
}
for (j = i; j < k; j++){
char temp;
if (stack[i] > stack[j]) {
temp = stack[j];
stack[j] = stack[i];
stack[i] = temp;
}
if (i, argc-1) push(' ');
}
show();
return 0;
}
}
I've been trying to make an output from the string "im loving" alphabetically in descending order (ASCII based) using command line arguments like this: vonmliig, but the output was "m i" instead.
Looks like you are trying to sort as you build the stack. I would build the stack first, then sort.
int main(int argc, char**argv)
{
if (argc >= 3) {
// Build stack
for (int i = 1; i < argc; i++) {
int k = strlen(argv[i]);
for (int j = 0; j < k ; j++) {
push(argv[i][j]);
}
}
// Sort
for (int i = 0; i < stackindex; i++) {
for (int j = i; j < stackindex; j++){
if (stack[i] > stack[j]) {
char temp = stack[j];
stack[j] = stack[i];
stack[i] = temp;
}
}
}
show();
}
return 0;
}
Also, there is an error in the handling of stackindex in push().
int push(char in)
{
char *temp = realloc(stack, stackindex + 1);
if (!temp) {
// Handle error
return -1;
}
stack = temp;
stack[stackindex++] = in;
return 1;
}
char pop()
{
if (stackindex) return stack[--stackindex];
else return 0;
}
void show()
{
do {
printf("%c", pop());
} while (stackindex);
}
#include <stdio.h>
#include <stdlib.h>
#include <limits.h>
#include <string.h>
#include <mpi.h>
#define MaxSize 50
typedef int ElementType;
typedef int Position;
typedef int Status;
typedef struct SeqStack
{
ElementType Data[MaxSize];
Position Top;
int (*Push)(struct SeqStack *L);
int (*Pop)(struct SeqStack *L , int e);
int (*isEmpty)(struct SeqStack s);
Status (*isFull)(struct SeqStack s);
}SeqStack;
int Push(SeqStack *L)
{
if(L->Top == 0)
{
return 0;
}
printf("%d ",L->Data[--L->Top]);
return 1;
}
int Pop(SeqStack *L , int e)
{
if(L->Top==MaxSize -1)
{
return 0;
}
L->Data[L->Top++] = e;
return 1;
}
int isEmpty(SeqStack s)
{
if(s.Top != 0)
{
return 1;
}
return 0;
}
Status isFull(SeqStack s)
{
if(s.Top != MaxSize -1)
{
return 1;
}
return 0;
}
int global_max;
int ans = INT_MAX;
void *tsp(int Dis[global_max][global_max],int v[],int N,int count,int currPos,int cost,int sum,int* result,int temp[],int make_log){
temp[0]=1;
//int mode;
//printf("count:%d\n",count);
if(count == N&&Dis[currPos][1]>0){
//printf("Ans:%d,cost:%d\n",ans,cost);
if(make_log == 1){
char str[100]={'\0'};
char output[100]={'\0'};
//printf("Ans:%d,cost:%d\n",ans,cost);
FILE *log;
for(int i=0; i<N;i++){
if (i!=N-1){
sprintf(str,"%d",temp[i]);
strcat(output,str);
strcat(output,",");
}else{
sprintf(str,"%d",temp[i]);
strcat(output,str);
strcat(output,"=");
}
}
sprintf(str,"%d",cost);
strcat(output,str);
strcat(output,"\n");
log=fopen("log.txt","a");
fputs(output,log);
fclose(log);
}
if(sum> cost){
sum = cost;
ans = cost;
//printf("every ans is %d\n\n\n\n",ans);
for (int i=0;i<N;i++){
//printf("temp[%d]=%d,",i,temp[i]);
result[i]=temp[i];
//printf("result[%d]=%d,",i,result[i]);
}
}
//ans = min(ans,cost + Dis[1][currPos]);
return result;
}
for (int i = 1;i<N+1;i++){
//printf("!!!!!!! v[%d] = %d\n",i,v[i]);
if(v[i]==0&&Dis[currPos][i]>0){
//printf("cost + Dis: %d + %d\n",cost,Dis[currPos][i]);
if(cost + Dis[currPos][i] <= ans||count==N-1){
v[i] = 1;
temp[count] = i;
//printf("\ntemp[%d] = %d\n",count,temp[count]);
//printf("currPos:%d,i:%d,count:%d\n",currPos,i,count);
//printf("Ans:%d,cost:%d\n",ans,cost);
result = tsp(Dis,v,N,count + 1,i,cost + Dis[currPos][i],sum,result,temp,make_log);
//mode = 0;
v[i]= 0;
if(count==1){
for(int j = 2;j<N+1;j++){
v[j]= 0;
}
}
}else{
//printf("currPos:%d,i:%d,count:%d\n",currPos,i,count);
temp[count] = i;
for (int k = N-1;k>count;k--){
temp[k] = 0;
}
int v_copy[N];
for (int o = 1;o<N+1;o++){
v_copy[o] = v[o];
// if(currPos==3&&i==4){
// printf("v_copy[%d] = %d//",o,v_copy[o]);
// }
}
for(int j = 2;j< N + 1;j++){
if(v[j]==0){
v[j] = 1;
}
}
result = tsp(Dis,v,N,N,N,cost + Dis[currPos][i],sum,result,temp,make_log);
//printf("Fuck currpos:%d\n",currPos);
for (int o = 1;o<N+1;o++){
v[o] = v_copy[o];
// if(currPos==3&&i==2){
// printf("v[%d] = %d//",o,v[o]);
// }
}
if(count==1){
for(int j = 2;j<N+1;j++){
v[j]= 0;
}
}
}
}
}
return result;
};
void change(int n){
global_max = n;
};
int main(int argc, char const *argv[])
{
int N;
int size = 1;
int count = 1;
int log = 0;
int nthreads,my_rank;
MPI_Init(&argc, &argv);
MPI_Comm_size(MPI_COMM_WORLD, &nthreads);
MPI_Comm_rank(MPI_COMM_WORLD, &my_rank);
if(argc > 2){
log = 1;
}
char x[100] = {0};
char filename[100] = {};
strcat(filename,argv[1]);
strcat(filename,".txt");
//printf("%s\n",filename);
FILE *fp=fopen(filename,"r");
if(fp==NULL){
printf("Cannot open the file,strike any key to exit!\n");
getchar();
exit(0);
}
for (int i = 0;!feof(fp);i++){
fscanf(fp,"%hhd",&x[i]);
}
N=x[0];
change(N);
int* result;
result = (int *)malloc(sizeof(int) * global_max);
int Dis[N][N], City[N];
for(int i=1;i<N;i++){
size=size*i;
}
char y[size];
for (int i=1;i<size+1;i++){
y[i] = x[i];
//printf("%d\n",y[i]);
}
for(int i=2; i < N + 1; i++){
for(int j=1; j < i ; j++){
Dis[j][i] = y[count];
Dis[i][j] = y[count];
count+=1;
//printf("(%d,%d),(%d,%d)",j,i,i,j);
//printf("%d\n",Dis[j][i]);
}
}
for(int i=0;i<N;i++){
City[i]=i + 1;//create the number of city with 1 ...... N
}
int curr_constraint = 0;
int v[N+1];
for (int i = 1; i < N+1; i++){
v[i] = 0;
}
for(int i = 1;i<N+1;i++){
curr_constraint += Dis[i][i+1];
}
v[1]= 1;
int sum = INT_MAX;
//printf("orginal ans is %d\n",ans);
//printf("Dis map:\n");
for( int i= 1;i<N+1;i++){
for(int j =1;j<N+1;j++){
if(i==j){
Dis[i][j]=0;
}
//printf("%d ",Dis[i][j]);
}
//printf("\n");
}
//printf("The orginal constraint is %d\n",curr_constraint);
int temp[N];
int* city_divided;
int cityNumber;
int current_ans;
SeqStack s;
if(nthreads > 1){
int remain = N % (nthreads - 1);
//int group_n = N /(nthreads - 1);
if(remain !=0){
if(my_rank <= remain && my_rank != 0){
cityNumber = ((N - remain)/(nthreads - 1)) + 1;
city_divided = (int*)malloc(cityNumber*sizeof(int));
for (int i = 0; i <cityNumber; i++)
{
city_divided[i] = City[(my_rank-1)*cityNumber + 1];
}
}else{
cityNumber = ((N - remain) / (nthreads - 1));
city_divided = (int*)malloc(cityNumber*sizeof(int));
for (int i = 0; i <cityNumber; i++)
{
city_divided[i] = City[(my_rank-1)*cityNumber + 1];
}
}
}else{
cityNumber = N / (nthreads - 1);
city_divided = (int*)malloc(cityNumber*sizeof(int));
for (int i = 0; i <cityNumber; i++)
{
city_divided[i] = City[(my_rank-1)*cityNumber + 1];
}
}
if(my_rank==0){
MPI_Recv(&ans, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
for(int i=0;i<N;i++){
if(i != N-1){
printf("%d,",*(result+i));
}
else{
printf("%d",*(result+i));
}
}
printf("\n");
printf("Distance: %d\n",ans);
}
if(my_rank!=0){
for (int i = 0 ; i<cityNumber;i++){
current_ans = ans;
while(s.isEmpty(s)){
MPI_Recv(&ans, 1, MPI_INT, 0, 0, MPI_COMM_WORLD, MPI_STATUS_IGNORE);
result = tsp(Dis,v,N,1,city_divided[i],0,ans,result,temp,log);
s.Pop(&s,ans);
}
result = tsp(Dis,v,N,1,city_divided[i],0,ans,result,temp,log);
if(current_ans - ans > 0){
s.Push(ans);
MPI_Bcast(&ans,1,MPI_INT,0,MPI_COMM_WORLD);
}
}
}
}
else{
result = tsp(Dis,v,N,1,1,0,sum,result,temp,log);
}
for(int i=0;i<N;i++){
if(i != N-1){
printf("%d,",*(result+i));
}
else{
printf("%d",*(result+i));
}
}
printf("\n");
printf("Distance: %d\n",ans);
return 0;
}
I am trying to solve a special travelling salesman problem with mpi and c. I want make the master processor print the final information including the route and the shorest distance. the other processors with all city group run the tsp function, and when it has the shorter distance, use mpi_send or mpi_Bcast to other processors.Follow this logic, I meet a problem when I run the program.
enter image description here
I am trying to sort an array of structures of size 5500 using merge sort.
However, I am getting a segmentation fault pretty quickly because I am not allowed to use VLA. so I have to create 2 extra arrays of size 5500 each time I call merge-sort recursively.
I would appreciate a fix for my problem. I will provide my code here:
void merge(Student rightArr[], Student leftArr[], Student mergedArr[], int sizeOfRight, int sizeOfLeft) {
int rightArrIndex = 0;
int leftArrIndex = 0;
int mergedArrIndex = 0;
while (leftArrIndex < sizeOfLeft && rightArrIndex < sizeOfRight) {
char *ptrLeft, *ptrRight;
long gradeLeft = strtol(leftArr[leftArrIndex].grade, &ptrLeft, BASE_COUNT);
long gradeRight = strtol(rightArr[rightArrIndex].grade, &ptrRight, BASE_COUNT);
if (gradeLeft > gradeRight) {
mergedArr[mergedArrIndex] = rightArr[rightArrIndex];
rightArrIndex++;
} else {
mergedArr[mergedArrIndex] = leftArr[leftArrIndex];
leftArrIndex++;
}
mergedArrIndex++;
}
if (leftArrIndex == sizeOfLeft) {
for (int i = mergedArrIndex; i < (sizeOfLeft + sizeOfRight); i++) {
mergedArr[i] = rightArr[rightArrIndex];
rightArr++;
}
} else {
for (int i = mergedArrIndex; i < (sizeOfLeft + sizeOfRight); i++) {
mergedArr[i] = leftArr[leftArrIndex];
leftArr++;
}
}
}
void mergeSort(Student studentsArray[], int amountOfStudents) {
if (amountOfStudents <= 1) {
return;
}
int leftSize = (amountOfStudents / 2);
int rightSize = (amountOfStudents - leftSize);
Student leftArr[5500], rightArr[5500];
for (int i = 0; i < leftSize; i++) {
leftArr[i] = studentsArray[i];
}
for (int i = 0; i < rightSize; i++) {
rightArr[i] = studentsArray[i + leftSize];
}
mergeSort(leftArr, leftSize);
mergeSort(rightArr, rightSize);
merge(rightArr, leftArr, studentsArray, rightSize, leftSize);
}
Ok, I think this should do what you want. It assumes that Student and BASE_COUNT have been defined:
#include <stdlib.h>
#include <stdio.h>
void merge(Student studentsArr[],
int leftSize, int rightSize,
Student scratchArr[])
{
Student *leftArr = studentsArr;
Student *rightArr = studentsArr + leftSize;
int leftIx = 0, rightIx = 0, mergeIx = 0, ix;
while (leftIx < leftSize && rightIx < rightSize) {
long gradeLeft = strtol(leftArr[leftIx].grade, NULL, BASE_COUNT);
long gradeRight = strtol(rightArr[rightIx].grade, NULL, BASE_COUNT);
if (gradeLeft <= gradeRight) {
scratchArr[mergeIx++] = leftArr[leftIx++];
}
else {
scratchArr[mergeIx++] = rightArr[rightIx++];
}
}
while (leftIx < leftSize) {
scratchArr[mergeIx++] = leftArr[leftIx++];
}
// Copy the merged values from scratchArr back to studentsArr.
// The remaining values from rightArr (if any) are already in
// their proper place at the end of studentsArr, so we stop
// copying when we reach that point.
for (ix = 0; ix < mergeIx; ix++) {
studentsArr[ix] = scratchArr[ix];
}
}
void mergeSortInternal(Student studentsArray[],
int amountOfStudents,
Student scratchArr[])
{
if (amountOfStudents <= 1) {
return;
}
int leftSize = amountOfStudents / 2;
int rightSize = amountOfStudents - leftSize;
mergeSortInternal(studentsArray, leftSize, scratchArr);
mergeSortInternal(studentsArray + leftSize, rightSize, scratchArr);
merge(studentsArray, leftSize, rightSize, scratchArr);
}
#define MAX_ARR_SIZE 5500
void mergeSort(Student studentsArray[], int amountOfStudents)
{
if (amountOfStudents <= 1) {
return;
}
if (amountOfStudents > MAX_ARR_SIZE) {
fprintf(stderr, "Array too large to sort.\n");
return;
}
Student scratchArr[MAX_ARR_SIZE];
mergeSortInternal(studentsArray, amountOfStudents, scratchArr);
}
The top-level sort function is mergeSort, defined as in the original post. It declares a single scratch array of size MAX_ARR_SIZE, defined as 5500. The top-level function is not itself recursive, so this scratch array is only allocated once.
I want to print all possible paths from a given source and destination. But in my BFS code, it only shows the two paths, not the multiple path. For a directed graph where n = 4, edge = 6, given,
1-2
1-3
1-5
5-3
5-4
3-4
3-2
It should've printed 3 paths:
1-5-4
1-3-4
1-5-3-4
But it only shows this two paths
1-3-4
1-5-4
This is my sample code for finding the src to destination path
#include <stdio.h>
int queue1[100], state[100], parent[100];
int front = 0, rear = -1, maxSize = 100;
int count = 0;
int initial = 1, waiting = 2, visited = 3;
int n, e;
int adj[100][100];
bool isEmpty()
{
return count == 0;
}
bool isFull()
{
return count == maxSize;
}
void enqueue(int val)
{
if (!isFull())
{
if (rear == maxSize - 1)
{
rear = -1;
}
rear++;
queue1[rear] = val;
count++;
}
}
int dequeue()
{
int val = queue1[front];
front++;
if (front == maxSize)
{
front = 0;
}
count--;
return val;
}
void BFS_Traversal(int src, int des)
{
int done = 0;
enqueue(src);
state[src] = waiting;
parent[src] = -1;
printf("path ");
while (!isEmpty() && done == 0)
{
src = dequeue();
// printf("%d ",src);
state[src] = visited;
for (int i = 1; i <= n; i++)
{
if (adj[src][i] == 1 && state[i] == initial)
{
enqueue(i);
state[i] = waiting;
parent[i] = src;
if (i == des)
{
state[i] = initial;
int k = des;
do
{
printf("%d ", k);
k = parent[k];
} while (k != -1);
printf("\n");
}
}
}
}
}
int main()
{
int src, start, end, des;
scanf("%d%d", &n, &e);
for (int i = 1; i <= e; i++)
{
scanf("%d%d", &start, &end);
adj[start][end] = 1;
}
for (int i = 1; i <= n; i++)
{
state[i] = initial;
}
for (int k = 1; k <= n; k++)
{
parent[k] = -1;
}
scanf("%d%d", &src, &des);
BFS_Traversal(src, des);
}
As, you can see 1-5-3-4 path is not showing because they are already visited. How should I modify this code to print all possible paths?
I want to remove element from b->array as shown in below code:removeItem function
I have tried to remove 12.12 from the b->array = {11.11,12.12,13.13}but it leads to segmentation fault instead of printing {11.11,13.13}. can anybody help to get rid of it?
typedef struct
{
float val;
}data;
typedef struct
{
data **array;
int size;
}bag;
int main(int argc,char* argv[])
{
bag *str = createBag();
#ifdef DEBUG
printf("Inital values: %p %d\n",str->array,str->size);
#endif
data *iptr = createData(10.10);
data *iptr1 = createData(11.11);
data *iptr2 = createData(12.12);
data *iptr3 = createData(13.13);
data *iptr4 = createData(14.14);
#ifdef DEBUG
printf("%f\n",iptr->val);
#endif
addData(str,iptr);
addData(str,iptr1);
addData(str,iptr2);
addData(str,iptr3);
addData(str,iptr4);
printBag(str);
data *ptr = getData(str,4);
printf("Data item 4 is:%f\n",ptr->val);
int b = getBagSize(str);
printf("Size of bag: %d\n",b);
removeBack(str);
printBag(str);
removeFront(str);
printBag(str);
//cleanBag(str);
int s = searchBag(str,10.10);
printf("%d\n",s);
removeItem(str,12.12);
printBag(str);
return 0;
}
bag* createBag()
{
bag *str = (bag*)malloc(sizeof(bag));
str->array = NULL;
str->size = 0;
return str;
}
data* createData(float v)
{
data *iptr = (data*)malloc(sizeof(data));
iptr->val = v;
return iptr;
}
void addData(bag* b, data* d)
{
b->size++;
data** array1 = (data**)malloc(sizeof(data*)* b->size);
if(b->array!= NULL)
{
int i;
for(i = 0; i<b->size;i++)
{
array1[i] = b->array[i];
}
}
free(b->array);
array1[b->size-1] = d;
b->array = array1;
}
void printBag(bag *b)
{
int i;
for(i=0; i<b->size;i++)
{
printf("%f\n",b->array[i]->val);
}
}
data* getData(bag *b, int pos)
{
if(pos>5)
{
printf("change array position\n");
}
return b->array[pos];
}
int getBagSize(bag *b)
{
return b->size;
}
void removeBack(bag *b)
{
b->size--;
free(b->array[b->size]);
data **array2 = (data**)malloc(sizeof(data*)* b->size);
if(b->array!= NULL)
{
int i;
for(i = 0; i<b->size;i++)
{
array2[i] = b->array[i];
#ifdef DEBUG
printf("%f\n",array2[i]->val);
#endif
}
free(b->array);
b->array = array2;
}
}
void removeFront(bag *b)
{
b->size--;
free(b->array[0]);
data **array2 = (data**)malloc(sizeof(data*)* b->size);
if(b->array!= NULL)
{
int i;
for(i = 0; i<b->size;i++)
{
array2[i] = b->array[i+1];
#ifdef DEBUG
printf("%f\n",array2[i]->val);
#endif
}
free(b->array);
b->array = array2;
}
}
/*void cleanBag(bag *b)
{
int i;
for(i=0;i<b->size;i++)
{
free(b->array[i]);
}
free(b->array);
free(b);
}*/
int searchBag(bag *b,float v)
{
int i;
for(i=0;i<b->size;i++)
{
if(b->array[i]->val==v)
{
return (i+1);
}
}
return -1;
}
void removeItem(bag *b, float v)
{
int flag = 0,i = 0;
flag = searchBag(b,v);
if(flag != -1)
{
data **array2 = (data**)malloc(sizeof(data*)*(b->size-1));
for(i = 0; i < (b->size); i++)
{
if(i == (flag-1))
{
i = i + 1;
continue;
}
array2[i] = b->array[i];
}
free(b->array);
b->size--;
b->array = array2;
}
else
{
printf("Element is not found\n");
}
}
There are two mistakes in your code.
searchBag returns 0, if the float value is not found in the bag.
However, the function removeItem test for if(flag != -1). It should test for if(flag != 0) instead.
The reason for the seg. fault you encountered also lies in the removeItem function.
Note how the memory allocated for array2 is for b->size-1 elements only. Valid array indices for this array are in the range of 0 ... b->size-2.
Now, look at the for loop, and you will note that the index variable i will run from 0 to b->size-1. Exactly in the last iteration i will become b->size-1, so the code tries to write at the location array2[b->size-1] which is beyond the allocated memory of array2.
A possible fix of the removeItem function could look like this:
void removeItem(bag *b, float v)
{
int flag = 0;
int oldArrayIndex = 0;
int newArrayIndex = 0;
flag = searchBag(b,v);
if(flag != 0)
{
data **array2 = (data**) malloc(sizeof(data*)*(b->size-1));
for(oldArrayIndex = 0; oldArrayIndex < (b->size); oldArrayIndex++)
{
if(oldArrayIndex != (flag-1))
{
array2[newArrayIndex] = b->array[oldArrayIndex];
newArrayIndex++;
}
}
free(b->array);
b->size--;
b->array = array2;
}
else
{
printf("Element is not found\n");
}
}