codewars几道练手题，随带原题链接

#include <stdbool.h>

bool xo (const char* str)
{
  int x_con=0,o_con=0;
  while(*str!='\0'){//这样也不会报错或者*str
    if(*str=='x'||*str=='X'){//区分大小写
      x_con++;
    }
    if(*str=='o'||*str=='O'){
      o_con++;
    }
    str++;//推进循环
  }
  if(o_con==x_con)
  return true;
  else return false;
}

Training on Exes and Ohs | Codewars

#include <stddef.h>

// do not allocate memory for the output array
// assign values to preallocated array results

void smaller(size_t length, const int array[length], size_t results[length]) {

    //  <----  hajime!
  size_t item=0;//注意题中定义的数据类型
  for(int i=0;i<length-1;i++){//注意！题中函数直接传输组
    for(int j=i+1;j<length;j++){
      if(array[i]>array[j]){
        item++;
      }
    }results[i]=item;//array[]是常量，不可修改存入results【】
    item=0;
  }results[length]=0;

}

Training on How many are smaller than me? | Codewars

#include <stddef.h>

int sum_no_duplicates(size_t length, const int array[length]) {

    //  <----  hajime!
  //桶思想
  int sum=0,a[100000]={0},item=0,len=(int)length;
  
  for(int i=0;i<len;i++){
    item=array[i];
    a[item]+=item;
  }
  for(int j=0;j<len;j++){
    if(a[j]==j){
      sum+=j;
    }
  }return sum;
}

Training on Sum a list but ignore any duplicates | Codewars

#include <stdbool.h>

bool xor(bool a, bool b) {
  if(a==b)
     
    return false;
    return true;
}

Training on Exclusive "or" (xor) Logical Operator | Codewars

int getAge(const char *inputString)
{
    // return correct age (int). Happy coding :)
  int item;
  item=(int)(*inputString-(char)'0');
  return item;
}

Training on Parse nice int from char problem | Codewars

#include<math.h>
int divisors(int n) {

    //  <----  hajime!
  int sum=0;
for(int i=1;i<n+1;i++){
  if(n%i==0){
    sum++;
  }
}
  
  return sum++;

}

Training on Count the divisors of a number | Codewars

unsigned convert_lojban(const char *lojban) {

    //  <----  hajime!
  int sum=0;
  while(*lojban){
    if(*lojban=='p') sum=sum*10+1;
        if(*lojban=='r') sum=sum*10+2;
    if(*lojban=='c') sum=sum*10+3;
    if(*lojban=='v') sum=sum*10+4;
    if(*lojban=='m') sum=sum*10+5;
    if(*lojban=='x') sum=sum*10+6;
    if(*lojban=='z') sum=sum*10+7;
    if(*lojban=='b') sum=sum*10+8;
    if(*lojban=='s') sum=sum*10+9;
    if(*lojban=='n') sum=sum*10+0;
    lojban+=2;
  }
  return sum;

}

Training on Lojban Numbers | Codewars

long long jie(long long a,long long b){
  long long sum=1;
  for(long long i=a;i>b;i--){
    sum*=i;
  }
  return sum;
}

long long factorial_division(long long n, long long d) {
  // Your turn !
  long long sum=1;
  if(n==0 && d==1) return 1;
  if(d==1) return jie(n,1);
  else return jie(n,d);
}

Training on Factorial division | Codewars

unsigned int countRedBeads (int n)
{
  if(n<=1) return 0;
  else return (n-1)*2;
  
}

Training on Simple beads count | Codewars

#include <stddef.h>

size_t str_count(const char *str, char letter) {
  size_t sum=0;
  //if(*str=='\0') return 0;
  while(*str){
    if(*str==letter) sum++;
    str++;
  }
  return sum;
}

Training on All Star Code Challenge #18 | Codewars