Delete the first group of consecutive negative
elements in the array.
void delNegative(int* arr, int& size) {
if (!check_prop(arr, size, neg)) return;
int ind_l, ind_f;//
if (arr[0] < 0) ind_f = 0;
if (arr[size - 1] < 0) ind_l = size - 1;
for (int i = 1; i < size; i++){
if (arr[i - 1] > 0 && arr[i] < 0) ind_f = i;
if (arr[i - 1] < 0 && arr[i] > 0) ind_l = i - 1;
}
if (ind_l < ind_f) ind_l = size - 1;
int ii = 0;
for (int i = 0; i < size; i++)
if (i > ind_l || i < ind_f) {
arr[ii] = arr[i];
ii++;
}
size -= ind_l - ind_f + 1;
}
There is this function, but it removes the last group of negative elements.
It needs to be redone for dynamic arrays
Related
When I free memory, the error "Program has triggered a breakpoint" occur. Check the code below, I wonder where is wrong ?
int SSavep(char *visited, int t, int n, int m)
{
int* map = (int*)malloc(m*n * sizeof(int));
int* q = (int*)malloc(m*n * sizeof(int));
int count = 0, cur = 0;
int begin = 0, end = 0;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
//set value for map
}
}
..........
if (t >= map[end]) {
free(map);
free(q);
return 0;
}
else{
free(map);
free(q);
return -1;
}
}
the entire code is as below:
static int dir[4][2] = { {0,1},{0,-1},{1,0},{-1,0} };
int SSavep(char *visited, int t, int n, int m)
{
int* map = (int*)malloc(m*n * sizeof(int));
int* q = (int*)malloc(m*n * sizeof(int));
int count = 0, cur = 0;
int begin = 0, end = 0;
for (int i = 0; i < m; i++) {
for (int j = 0; j < n; j++) {
if (visited[i*n + j] == '.')
map[i*n + j] = 0;
else if (visited[i*n + j] == '*')
map[i*n + j] = -1;
else if (visited[i*n + j] == 'p') {
map[i*n + j] = -12;
end = i*n + j;
}
else {
map[i*n + j] = -9;
begin = i*n + j;
}
}
}
q[count++] = begin;
while (cur < count && q[cur] != end) {
int i = q[cur] / n;
int j = q[cur] % n;
for (int k = 0; k < 4; k++) {
int ni = i + dir[k][0];
int nj = j + dir[k][1];
if (ni < 0 || ni >= m || nj < 0 || nj >= n || map[ni*n + nj]>0 || map[ni*n + nj] == -1)
continue;
map[ni*n + nj] = map[i*n + j] + 1;
q[count++] = ni*n + nj;
}
cur++;
}
if (map[end] > 0 && t >= map[end]) {
free(map);
free(q);
return 0;
}
else{
free(map);
free(q);
return -1;
}
}
You are getting error on >> free(q);
for m=n=4
int* q = (int*)malloc(m*n * sizeof(int));
q == [m*n*sizeof(int)] == 4*4*4 == 64 bytes == int[16];
Because you wrote beyond the address space reserved for pointer variable 'q'.
check 'count' variable before free(q). I've got 1208, called with:
char* visited = new char[100 * 100];
memset(visited, 0, 10000);
int res = SSavep(visited, 0, 4, 4);
Btw this algo looks alot like some path finding examining neighboring cells on map and assigning weights, right? If so there are many opensource solutions, why not using them instead of reinventing the wheel? There are links to opensource solutions on wiki Path Finding page:
https://en.wikipedia.org/wiki/Pathfinding
check the bottom of the page for links.
Given a set of numbers, check whether it can be partitioned into two subsets such that the sum of elements in both subsets is same or not
I am getting segmentation fault in C++(g++ 5.4) with a this problem.
This is where i submitted my solution in C++
https://practice.geeksforgeeks.org/problems/subset-sum-problem/0
I am checking if the array can be divided into two parts with equal sum. So I am just checking if there exists a subset with sum equal to half the sum of the array
I have implemented the below logic with dynamic programming
Let dp[i][j] denote yes or no whether a subset with sum j is possible to form with elements in the range [0, i](both inclusive) where i is 0-based index. I have done nothing new with this traditional problem. But I am getting segmentation fault. The program is giving correct output for small test cases. What mistake have I made
I haven't used any comments because I have done nothing new. Hope it is understandable.
#include <iostream>
#include <bits/stdc++.h>
#include<cstdio>
#define ll long long int
using namespace std;
bool isVowel(char c){
return c == 'a' || c == 'e' || c == 'i' || c == 'o' || c == 'u';
}
bool isLower(char c){
return 97 <= c && c <= 122;
}
int main() {
ios_base::sync_with_stdio(false);
cin.tie(NULL);
cout.tie(NULL);
cout << setprecision(10);
ll t, n;
cin >> t;
while (t--) {
cin >> n;
ll a[n];
ll sum = 0;
for (ll i = 0; i < n; i++) {
cin >> a[i];
sum += a[i];
}
if (sum % 2) {
cout << "NO" << '\n';
continue;
}
sum /= 2;
ll dp[n][sum + 1];
for (ll i = 0; i < n; i++) {
for(ll j = 0; j < sum + 1; j++) {
dp[i][j] = 0;
}
}
for (ll i = 0; i < n; i++) {
dp[i][a[i]] = 1;
dp[i][0] = 1;
}
for (ll i = 1; i < n; i++) {
for (ll j = 1; j < sum + 1; j++){
if (j - a[i] > 0) {
dp[i][j] = dp[i - 1][j - a[i]];
}
dp[i][j] |= dp[i - 1][j];
}
}
cout << (dp[n - 1][sum] ? "YES" : "NO") << '\n';
}
}
The segmentation fault is due to
ll dp[n][sum + 1];
Even though the constraints say 1 <= N<= 100, 0 <= arr[i]<= 1000, the test cases used are probably much larger, so ll dp[n][sum + 1] will end up taking some serious stack memory, use
bool dp[n][sum + 1];
It should work fine.
On a side note, avoid using ll randomly, use them according to the constraints.
I am trying to complete a task in MIPS.
It is needed to compare 2 strings in the next way: to count a number of each ascii symbol from 1 to 255 in both strings and and compare values for each symbol.
For a moment i have wrote piece of pseudo code in java just to visualize a problem. The part that i can't understand is how can i make a "search" of each ascii character in a string.
// array allAscii that suppose to contain all ascii symbols (i have made it
containing all zeros bacause in this java code it is not that much important)
int[] allAscii = new int[255]
String s1 = "ascii."; // first string
String s2 = "asciiz,"; // second string
int difference = 0;
for(int i = 0; i< allAscii.length; i++){
int count1 = 0; //counter for the character of the string1
int count2 = 0; //counter for the character of the string1
for(int k = 0; k<s1.length(); k++){
if( s1.charAt(k) == allAscii[i]) count1++;
}
for(int l = 0; l<s2.length(); l++){
if( s2.charAt(l) == allAscii[i]) count2++;
}
difference += Math.abs(count1- count2);
}
so as the result for strings "ascii." and "asciiz,"
symbols from 0 to 43: count1 = 0; count2 = 0; difference = 0;
',': count1 = 0; count2 = 1; difference = 1;
'.': count1 = 1; count2 = 0; difference = 1;
symbols from 47 to 96: count1 = 0; count2 = 0; difference = 0;
'a': count1 = 1; count2 = 1; difference = 0;
'c': count1 = 1; count2 = 1; difference = 0;
'i': count1 = 2; count2 = 2; difference = 0;
's': count1 = 1; count2 = 1; difference = 0;
'z': count1 = 0; count2 = 1; difference = 1;
and so on....
it is non needed to store amount of each letter. i need just to accumulate variable difference but i should run through ALL ascii symbols
I'm trying to do a pascal triangle but for some reason i have the error "Run-Time Check Failure #2 - Stack around the variable 'TP' was corrupted." Can someone help me, please?
#include <iostream>
using namespace std;
void main()
{
int TP[100][100] = { 0 }, n;
do
{
cout << "Digite a ordem do triangulo de pascal: ";
cin >> n;
} while (n < 0 || n > 100);
for (int j = 0; j < n; j++)
{
TP[j][0] = 1;
TP[j][j] = 1;
}
for (int i = 2; i < n + 1; i++)
for (int j = 1; TP[i][j] != 1; j++)
TP[i][j] = TP[i - 1][j - 1] + TP[i - 1][j];
for (int i = 0; i < n; i++)
{
cout << endl;
for (int j = 0; j != i + 1; j++)
cout << TP[i][j] << " ";
}
cout << endl << endl;
system("pause");
}
You go beyond the array boundaries in for (int i = 2; i < n + 1; i++) for i == n when n=100.
My code compiles but throws the following exception:
An unhandled exception of type 'System, Access Violation Exception' occured Additional Information: Attempted to read or write protected memory. . .
the error is related to s=s+a[z][r]*b[f][h]
Here a copy of the code:
#include"stdafx.h"
#include"iostream"
using namespace std;
int main()
{
int **a, **b;
int z, r, f, h, a_r, a_c, b_r, b_c, s = 0;
cout << "Enter the size of the matrix(nxm) :" << endl;
cin >> a_r >> a_c;
cout << "enter the size of the mask :" << endl;
cin >> b_r >> b_c;
a = (int **) malloc(10 * a_r);
for (int i = 0; i < a_c; i++)
{
a[i] = (int *) malloc(10 * a_c);
}
b = (int **) malloc(10 * b_r);
for (int i = 0; i < b_c; i++)
{
b[i] = (int *) malloc(10 * b_c);
}
for (int i = 0; i < a_r; i++)
{
for (int j = 0; j < a_c; j++)
{
a[i][j] = i + j;
}
}
for (int i = 0; i < b_r; i++)
{
for (int j = 0; j < b_c; j++)
{
b[i][j] = i + j;
}
}
int k = 1, d = 1;
for (int i = 0; i < a_r; i++)
{
for (int j = 0; j < a_c; j++)
{
for (int n = -1; n <= 1; n++)
{
for (int e = -1; e <= 1; e++)
{
z = i + n;
r = j + e;
f = k + n;
h = d + e;
if (z < 0 || z > a_r || r < 0 || r > a_c)
{
s = s + 0;
} else {
s = s + a[z][r] * b[f][h]; // runtime error occurs here
}
}
}
a[i][j] = s;
s = 0;
}
}
return 0;
}
Here is one problem:
if (z < 0 || z > a_r || r < 0 || r > a_c)
This should read:
if (z < 0 || z >= a_r || r < 0 || r >= a_c)
Otherwise you're potentially accessing out-of-bounds elements.