题解 | #头条校招#

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

// 比较函数，用于整数的升序排序
int compare(const void *a, const void *b) {
	int num1 = *(const int *)a;
	int num2 = *(const int *)b;
	
	if (num1 < num2)
		return -1;
	else if (num1 > num2)
		return 1;
	else
		return 0;
}

int main(int argc, char *argv[]) {
	int n;
	scanf("%d",&n);
	int difficulty[n];
	
	for(int i=0;i<n;i++){
		scanf("%d",&difficulty[i]);
	}
	
	qsort(difficulty, n, sizeof(int),compare);
	
	int add_count=0;
	
	int i=0;
	while(i+2<n){
		if(difficulty[i+1]-difficulty[i]<=10 && difficulty[i+2]-difficulty[i+1]<=10)
			i+=3;
		else if(difficulty[i+1]-difficulty[i]<=10){
			//前两个之间的差值小于10，在后面补充一个题目
			add_count++;
			i+=2;
		}
		else if(difficulty[i+1]-difficulty[i]>10 && difficulty[i+1]-difficulty[i]<=20){
			//前两个之间的差小于20但是大于10
			add_count++;
			i+=2;
		}
		else {
			add_count+=2;
			i++;
		}
	}
	
	if((n-i) !=0 )
		add_count+=(3-(n-i));
	
	printf("%d",add_count);
	
	return 0;
	
	
}