题解 | 排序危机

#include <stdio.h>
#include <stdlib.h>
#include <ctype.h>


int main() {
    int n;
    scanf("%d",&n);
    char *low = (char*)malloc(n + 1);
    char *num = (char*)malloc(n + 1);
    char *upp = (char*)malloc(n + 1);
    char *str = (char*)malloc(n + 1);

    int low_co = 0, num_co = 0, upp_co = 0;



    scanf("%s",str);
    for(int i = 0;i < n;i++)
    {
        if(islower(str[i]))
        {
            low[low_co++] = str[i];            
        }
        if(isdigit(str[i]))
        {
            num[num_co++] = str[i];            
        }
        if(isupper(str[i]))
        {
            upp[upp_co++] = str[i];            
        }
    }

    printf("%s%s%s",low,num,upp);
    
    free(low);
    free(num);
    free(upp);
    free(str);

    
    return 0;
}