02x01 - Stacks Using an Array

//HEAD#include "stdio.h"#include "string.h"#include "stdlib.h"#include "math.h"

//BODY
int stackArr[100005];
int top = -1; //Stores the index of the topmost element on the stack
void push(int x) { //- Insert an element onto the top of the stack
    stackArr[++top] = x;
}
int peek() // - Returns the topmost element on the stack
{
    return stackArr[top];
}
void pop() // - Removes an element from the top of the stack
{
    top--;
}
int empty() //- Returns 1 if the stack is empty and 0 otherwise
{
    if (top == -1) return 1;
    else return 0;
}

//TAIL
int main() {
    int n;
    top = -1;
    scanf("%d", & n);
    for (int i = 0; i < n; i++) {
        int t, x;
        scanf("%d", & t);
        if (t == 1) {
            scanf("%d", & x);
            push(x);
        } else if (t == 2) {
            if (empty()) {
                printf("Invalid\n");
            } else {
                pop();
            }
        } else if (t == 3) {
            if (empty()) {
                printf("Invalid\n");
                continue;
            }
            for (int j = top; j >= 0; j--) {
                printf("%d ", stackArr[j]);
            }
            printf("\n");
        } else {
            if (empty()) {
                printf("Invalid\n");
                continue;
            }
            printf("%d\n", peek());
        }
    }
    return 0;
}

02x02 - Stacks Using a LinkedList

//HEAD#include "stdio.h"#include "string.h"#include "stdlib.h"#include "math.h"
//BODY
struct stackNode {
    int val;
    struct stackNode * next;
};
typedef struct stackNode stackNode;
stackNode * stackHead; // Head Pointer for stack LinkedList
void push(int x) { // Insert an element onto the top of the stack
    stackNode * node = malloc(sizeof(stackNode));
    node - > val = x;
    node - > next = NULL;
    if (stackHead == NULL) stackHead = node;
    else {
        node - > next = stackHead;
        stackHead = node;
    }
}
int peek() { // Returns the topmost element on the stack
    return stackHead - > val;
}
void pop() { // Removes an element from the top of the stack
    stackHead = stackHead - > next;
}
int empty() { // Returns 1 if the stack is empty and 0 otherwise
    if (stackHead == NULL) return 1;
    return 0;
}
//TAIL
int main() {
    int n;
    stackHead = NULL;
    scanf("%d", & n);
    for (int i = 0; i < n; i++) {
        int t, x;
        scanf("%d", & t);
        if (t == 1) {
            scanf("%d", & x);
            push(x);
        } else if (t == 2) {
            if (empty()) {
                printf("Invalid\n");
            } else {
                pop();
            }
        } else if (t == 3) {
            if (empty()) {
                printf("Invalid\n");
                continue;
            }
            stackNode * j = stackHead;
            while (j) {
                printf("%d ", j - > val);
                j = j - > next;
            }
            printf("\n");
        } else {
            if (empty()) {
                printf("Invalid\n");
                continue;
            }
            printf("%d\n", peek());
        }
    }
    return 0;
}

The Freeman Problem#include < cmath > #include < cstdio > #include < vector > #include < iostream > #include < algorithm > using namespace std;

int safe(int n, int k) {
    if (n == 1) return 1;
    return (safe(n - 1, k) + k - 1) % n + 1;
}

int main() {
    int n, k;
    cin >> n >> k;
    cout << safe(n, k);
    return 0;
}

01x09 - Tisha and Orange Sorting#include < cmath > #include < cstdio > #include < vector > #include < iostream > #include < algorithm > using namespace std;

int partition(int arr[], int l, int r) {
    int pivot = arr[r];
    int i = l - 1;
    for (int j = l; j <= r - 1; j++) {
        if (arr[j] <= pivot) {
            i++;
            int temp = arr[i];
            arr[i] = arr[j];
            arr[j] = temp;
        }
    }
    int temp = arr[i + 1];
    arr[i + 1] = arr[r];
    arr[r] = temp;
    return (i + 1);
}

void Quicksort(int arr[], int l, int r) {
    if (l < r) {
        int p = partition(arr, l, r);
        cout << p << endl;
        for (int i = l; i <= r; i++)
        cout << arr[i] << " ";
        cout << endl;
        Quicksort(arr, l, p - 1);
        Quicksort(arr, p + 1, r);
    }
}

int main() {
    int n;
    cin >> n;
    int arr[n];
    for (int i = 0; i < n; i++)
    cin >> arr[i];
    Quicksort(arr, 0, n - 1);
    return 0;
}

01x08 - Orange Partitioning#include < cmath > #include < cstdio > #include < vector > #include < iostream > #include < algorithm > using namespace std;


int main() {
    /* Enter your code here. Read input from STDIN. Print output to STDOUT */
    int n;
    cin >> n;
    int k = 0;
    int orange[n];
    for (int i = 0; i < n; i++)
    cin >> orange[i];

    for (int i = 0; i < n - 1; i++)
    if (orange[i] <= orange[n - 1]) {
        int temp = orange[i];
        orange[i] = orange[k];
        orange[k] = temp;
        k++;
    }
    int temp = orange[k];
    orange[k] = orange[n - 1];
    orange[n - 1] = temp;
    for (auto i: orange)
    cout << i << " ";
    return 0;
}
Setting Validate Copy Format