class box{
int l,w,h;
box(int a,int b,int c){
l = a;w = b;h = c;
};
};
bool cmp(box a,box b){
return a.l*a.w<b.l*b.w;
}
class Solution{
public:
/*The function takes an array of heights, width and
length as its 3 arguments where each index i value
determines the height, width, length of the ith box.
Here n is the total no of boxes.*/
int maxHeight(int h[],int w[],int l[],int n)
{
//Your code here
struct box b[(3*n)]={};
int j = 0;
for(int i = 0 ; i< n; ++ i){
b[j++] = box(min(l[i],w[i]),max(l[i],w[i]),h[i]);
b[j++] = box(min(l[i],h[i]),max(l[i],h[i]),w[i]);
b[j++] = box(min(w[i],h[i]),max(w[i],h[i]),l[i]);
}
n*=3;
sort(b,b+n,cmp);
int dp[n];
for(int i = 0 ; i< n; ++ i){
dp[i] = b[i].h;
}
int ans = INT_MIN;
for(int i = 1; i< n; ++ i){
for(int j = 0; j< i; ++ j){
if(b[i].l>b[j].l and b[i].w>b[j].w and dp[i]<dp[j]+b[i].h)
dp[i] = b[i].h+dp[j];
}
ans = max(ans,dp[i]);
}
return ans;
}
};
The code above shows an error that struct variables takes 3 arguments and only 1 given as shown.
Please help me out of this. Thanks.
Also please provide some good references from where I could get more idea on these kinds of topics. Like sites from where I could learn these type of hints and secrets of language.
I got it. Here I had not written the default initializers functions and that is why it is showing this error.
Also I need to change the access modifier to public.
So I changed the code of struct declaration to something like this.
Related
I tried to implement selection sorting in C++，when i encapsulate the swap function, the output shows a lot of zeros.But at beginning of array codes still work.When I replace swap function with the code in the comment, the output is correct.
I am so confused by this result, who can help me to solve it.
#include <iostream>
#include <string>
using namespace std;
template<class T>
int length(T& arr)
{
return sizeof(arr) / sizeof(arr[0]);
}
void swap(int& a, int& b)
{
a += b;
b = a - b;
a = a - b;
}
int main()
{
int array[] = { 2,2,2,2,6,56,9,4,6,7,3,2,1,55,1 };
int N = length(array);
for (int i = 0; i < N; i++)
{
int min = i; // index of min
for (int j = i + 1;j < N; j++)
{
if (array[j] < array[min]) min = j;
}
swap(array[i],array[min]);
// int temp = array[i];
// array[i] = array[min];
// array[min] = temp;
}
for (int i = 0; i < N; i++)
{
int showNum = array[i];
cout << showNum << " ";
}
return 0;
}
Problem is that your swap function do not work if a and b refer to same variable. When for example swap(array[i], array[i]) is called.
Note in such case, this lines: b = a - b; will set b to zero since a and b are same variable.
This happens when by a chance i array element is already in place.
offtopic:
Learn to split code into functions. Avoid putting lots of code in single function especially main. See example. This is more important the you think.
Your swap function is not doing what it is supposed to do. Just use this instead or fix your current swap.
void swap(int& a, int& b){
int temp = a;
a = b;
b = temp;
}
void initialize(int arr[], int size[], int n)
{
int i;
for(i = 1; i <= n; i++) {
arr[i] = i;
size[i] = 1;
}
}
class hell
{
public:
int edges;
int vertices;
pair<int , pair<int,int>> p[100000];
int disjoint_set[10000];
int cc_size[10000]; // size of connected components
hell(int e, int v)
{
edges = e;
vertices = v;
initialize(disjoint_set, cc_size, vertices);
}
};
In the following class when I create an object using vertices=100000 and edges=100000, the code stops working. But when we remove the initialize(disjoint_set, cc_size, vertices) it starts working. I don't have any clue to such behavior. Please guide me.
Arrays in C++ are zero indexed, which means that valid index is in [0..n[ range. Your code does it wrong:
for(i = 1; i <= n; i++) {
arr[i] = i;
size[i] = 1;
}
it should be:
for(i = 0; i < n; i++) {
arr[i] = i + 1;
size[i] = 1 + 1;
}
or better use algo std::iota() and std::fill():
std::iota( arr, arr + n, 1 );
std::fill( size, size + n, 1 );
and you better use std::vector, which will adjust its size properly, rather than have huge array.
I cant find out whats wrong with this part of my program, i want to find out most occuring number in my structure(array), but it finds only the last number :/
void Daugiausiai(int n)
{
int max = 0;
int sk;
for(int i = 0; i < n; i++){
int kiek = 0;
for(int j=0; j < n; j++){
if(A[i].datamet == A[j].datamet){
kiek++;
if(kiek > max){
max = kiek;
sk = A[i].datamet;
}
}
}
}
}
ps. its only a part of my code
You haven't shown us enough of your code, but it is likely that you are not looking at the real result of your function. The result, sk is local to the function and you don't return it. If you have global variable that is also named sk, it will not be touched by Daugiausiai.
In the same way, you pass the number of elements in your struct array, but work on a global struct. It is good practice to "encapsulate" functions so that they receive the data they work on as arguments and return a result. Your function should therefore pass both array length and array and return the result.
(Such an encapsulation doesn't work in all cases, but here, it has the benefit that you can use the same function for many different arrays of the same structure tape.)
It is also enough to test whether the current number of elements is more than the maximum so far after your counting loop.
Putting all this together:
struct Data {
int datamet;
};
int Daugiausiai(const struct Data A[], int n)
{
int max = 0;
int sk;
for (int i = 0; i < n; i++){
int kiek = 0;
// Count occurrences
for(int j = 0; j < n; j++){
if(A[i].datamet == A[j].datamet) kiek++;
}
// Check for maximum
if (kiek > max) {
max = kiek;
sk = A[i].datamet;
}
}
return sk;
}
And you call it like this:
struct Data A[6] = {{1}, {2}, {1}, {4}, {1}, {2}};
int n = Daugiausiai(A, 6);
printf("%d\n", n); // 1
It would be nice if you had english variable names, so I could read them a bit better ^^. What should your paramter n do? Is that the array-length? And what should yout funtion do? It has no return value or something.
int getMostOccuring(int array[], int length)
{
int current_number;
int current_count = 0;
int most_occuring_number;
int most_occuring_count = 0;
for (int i = 0; i < length; i++)
{
current_number = array[i];
current_count = 0;
for (int j = i; j < length; j++)
{
int test_number = array[j];
if (test_number == current_number)
{
current_count ++;
if (current_count > most_occuring_count)
{
most_occuring_number = current_number;
most_occuring_count = current_count;
}
}
}
}
return most_occuring_number;
}
this should work and return the most occuring number in the given array (it has a bad runtime, but is very simple and good to understand).
My code is trying to implement the union-find algorithm and I have the id[] array and the sz[] array. I initialize them in the Union-Find constructor, but once I try to use those arrays in the methods within the Union-Find class, it changes all the array values to 1. I don't understand why. Is there something obvious that I'm missing??
H File
class UnionFind{
public:
UnionFind(int size);
void join(int x, int y);
int connected(int x, int y);
int find(int x);
private:
int size;
int id[];
int sz[];
};
CPP File
UnionFind::UnionFind(int size){
this->id[size] = id[size];
for(int i = 0; i < size; i++){
id[i] = i;
}
for(int i = 0; i < size; i++){
sz[i] = 1;
}
}
int UnionFind::find(int l){
//Path Compression Finding the Root
for(int i = 0; i < 5; i++){
}
while(l != id[l]){
id[l] = id[id[l]];
l = id[l];
}
return l;
}
void UnionFind::join(int x, int y){
int m = find(x);
int n = find(y);
if(sz[m] < sz[n]){
id[m] = n;
sz[n] += sz[m];
}
else{
id[n] = m;
sz[m] += sz[n];
}
}
int UnionFind::connected(int x, int y){
if(find(x) == find(y)){
return 1;
}
else{
return 0;
}
}
From the comments.
you can't have int id[] as a class member,
use std::vector (resize and fill in constructor),
your forgot to set member size in constructor,
your find algorithm uses path halving not path compression (this does not affect the running time).
Side note: you can use a single array/vector to implement your disjoint set data structure.
void sort(int* A,int l)
{
int j;
int B[l];
for(int i=0;i<l;i++)
{
j = largest(A,l);
B[l-i-1] = A[j];
A[j] = -1;
}
A = B;
}
int main()
{
.
int C[3] = {x,y,z};
...
sort(C,3);
cout<<C[0]<<C[1];
}
output is coming to be -1-1
But if we assign A[0] = B[0] and so on, then we are getting the right answer.
PS: I've tried using *A = *B, which is only giving the first element to be correct.
When you assign A = B, you re-assign a local variable that holds a pointer to the first element of your array. This assignment will not change anything in main. In particular, the contents of A will not be affected.
You must copy all the elements from B to A after you have finished your sorting:
void sort(int *A, int l)
{
int j;
int B[l];
// sort into temporary array B
for (int i = 0; i < l; i++) {
j = largest(A, l);
B[l - i - 1] = A[j];
A[j] = -1;
}
// copy temporary array B to result array A
for (int i = 0; i < l; i++) A[i] = B[i];
}
But if you look at it, Amol Bavannavar was basically right: You don't have to check the whole array for the largest element each time. It is enough to check the remaining elements. So instead of assigning a low value to "used" elements, you could swap the largest elements to the end. When you do that, you'll see that the processed elements are at the end, the unprocessed elements are at the beginning. Then you can do your sorting in place without the need of a temporary array:
void sort2(int *A, int l)
{
while (l) {
int j = largest(A, l--);
int swap = A[j]; A[j] = A[l]; A[l] = swap;
}
}
There are many wrong uses of code in your example, for instance:
int B[l];
cannot be done, if you do it like this l must have a constant value.
A = B;
will perform a shallow copy instead of a deep copy.
You can see the diffrence here: What is the difference between a deep copy and a shallow copy?
cout<<C[0]<<C[1];
will print the numbers joined together without parsing.
As to how to fix this code one implementation you might be aiming towards can be:
#include <iostream>
using namespace std;
int largest(int* A, int l)
{
int big=-1;
int i;
int index=0;
for(i=0;i<l;i++)
{
if(A[i]>big)
{
big=A[i];
index=i;
}
}
return index;
}
void sort(int* A,int l)
{
int j;
int *B=new int[l];
for(int i=0;i<l;i++)
{
j = largest(A,l);
B[l-i-1] = A[j];
A[j] = -1;
}
for(int i=0;i<l;i++)
{
A[i]=B[i];
}
}
int main()
{
int C[3] = {2,5,1};
sort(C,3);
cout<<C[0]<<" "<<C[1];
return 1;
}