Question

Below code is working for Array{ 4 5 3 7 2 }, but not working for other test case given on HackerRank Site. What is error in my code? Am I doing any wrong while merging the two array a1[] and a2[] into the ar[] ?

https://www.hackerrank.com/challenges/quicksort1

#include <stdio.h>
#include <string.h>
#include <math.h>
#include <stdlib.h>
#include <assert.h>
void partition(int ar_size, int *  ar) {
    int a1[100], a2[100];
    int p = ar[0];
    int i=0, j=0 , k=0;
    for(i=0; i<ar_size; i++){
        if(ar[i] < p)
         {
            a1[j] = ar[i];
            j++;
        }      
        else if(ar[i] >= p){
            a2[k] = ar[i];
            k++;
        }            
    }

    i=0, j=0 , k=0;

    while(a1[i]){
        ar[i] = a1[j];
        i++;
        j++;
    }
    while(a2[k]){
        ar[i] = a2[k];
        i++;
        k++;
    }

    for(i=0; i<ar_size; i++){
        printf("%d ", ar[i]);          
    }

}
int main(void) {

   int _ar_size;
scanf("%d", &_ar_size);
int _ar[_ar_size], _ar_i;
for(_ar_i = 0; _ar_i < _ar_size; _ar_i++) { 
   scanf("%d", &_ar[_ar_i]); 
}

partition(_ar_size, _ar);

   return 0;
}

Answer 1

 int _ar_size;
scanf("%d", &_ar_size);
int _ar[_ar_size], _ar_i;

初始化变量或数组时，无法初始化数字未知的数组。您应该知道需要多少（如果您不知道所需的大小，只需使用大数字初始化数组或使用链表）因为电脑或者其他什么应该知道他将在内存中分配多少。

Answer 2

删除i = 0，j = 0，k = 0;以下是什么，并尝试以下

while(k--){
    ar[k+j] = a2[k];
}
while(j--){
    ar[j] = a1[j];
}

What is error in partition code?

2 个答案: