#YBT整理 排序算法的例题

车厢重组

门儿

冒泡排序，每次交换即为调转车厢，ans++

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
int a[10000];
int ans; 
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++) cin >> a[i];
	for(int i = 1;i <= n; i++){
		for(int j = 1;j <= n - i; j++){
			if(a[j] > a[j+1]){
				swap(a[j],a[j+1]);
				ans++;
			}
		}
	} 
	cout << ans << endl;
	return 0;
}//lcez_cyc

求逆序对

传送

归并排序。合并的时候，被放进去的数字右边的所有数字都可以组成逆序对。

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
long long ans = 0;
int a[500400];
int b[500400];
int L[500400],R[500400];
int RT = 0;
void msort(int l,int r){
	if(l == r) return;
	int mid = (l+r) >>1;
	msort(l,mid);
	msort(mid+1,r);
	int i = l,j = mid + 1;
	int cnt = l;
	while(j <= r && i <= mid){
		if(a[i] > a[j]){
			ans += mid - i + 1;
			b[cnt++] = a[j++];
		}
		if(a[i] <= a[j]){
			b[cnt++] = a[i++];
		}
	}
	while(j <= r)
		b[cnt++] = a[j++];
	while(i <= mid)
		b[cnt++] = a[i++];
	for(int i = l;i <= r; i++)
		a[i] = b[i];
}
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++){
		cin >> a[i];
	}
	msort(1,n);
	cout << ans << endl;
	return 0;
}

谁考了第k名

小门

这个就很水了就不说了

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n,k;
struct STU{
	int num;
	double sco;
}stu[1000];
bool cmp(STU a,STU b){
	return a.sco > b.sco;
}
int main(){
	cin >> n >> k;
	for(int i = 1;i <= n; i++)
		cin >> stu[i].num >> stu[i].sco;;
	sort(stu + 1,stu + 1 + n,cmp);
	cout << stu[k].num << ' ' << stu[k].sco << endl;
	return 0;
}

奇数单增序列

门门

这个也挺水，直接把偶数扔掉就好了

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
int a[1000];
int main(){
	int tot = 1;
	cin >> n;
	for(int i = 1;i <= n; i++){
		int f;
		cin >> f;
		if(f % 2)
			a[tot++] = f; 
	}
	tot--;
	sort(a+1,a+tot+1);
	for(int i = 1;i <= tot;i++){
		cout << a[i];
		if(i != tot) cout <<',';
	}
	return 0;
}

成绩排序

门

水题

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n,k;
struct STU{
	string name;
	int sco;
}stu[1000];
bool cmp(STU a,STU b){
	return a.sco >= b.sco;
}
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++)
		cin >> stu[i].name >> stu[i].sco;;
	sort(stu + 1,stu + 1 + n,cmp);
	for(int i = 1;i <= n; i++){
		cout << stu[i].name << ' ' << stu[i].sco << endl;
	}
	return 0;
}

奖学金

门门

多关键字排序。

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n,k;
struct STU{
	int num;
	int sco;
	int chi,mat,eng;
}stu[1000];
bool cmp(STU a,STU b){
	if(a.sco != b.sco) return a.sco > b.sco;
	if(a.chi != b.chi) return a.chi > b.chi;
	return a.num < b.num;
}
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++){
		stu[i].num = i;
		cin >> stu[i].chi >> stu[i].mat >> stu[i].eng;
		stu[i].sco = stu[i].chi + stu[i].mat + stu[i].eng;
	}
	sort(stu + 1,stu + 1 + n,cmp);
	for(int i = 1;i <= 5; i++){
		cout << stu[i].num << ' ' << stu[i].sco << endl;
	} 
	return 0;
}

分数线划定

门

先划定分数线，确定人数，再输出入选的人

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n,k;
struct STU{
	int num;
	int sco;
}stu[9999];
bool cmp(STU a,STU b){
	if(a.sco != b.sco) return a.sco > b.sco;
	return a.num < b.num;
}
int main(){
	cin >> n >> k;
	for(int i = 1;i <= n; i++)
		cin >> stu[i].num >> stu[i].sco;
	sort(stu + 1,stu + 1 + n,cmp);
	k = k *3 / 2;
	int i;
	for(i = 1;stu[i].sco >= stu[k].sco; i++);
	i--;
	cout <<stu[i].sco << ' ' << i << endl;
	for(i = 1;stu[i].sco >= stu[k].sco; i++){
		cout << stu[i].num << ' ' << stu[i].sco << endl;
	}
	return 0;
}

整数奇偶排序

整数奇偶排序

设定两个指针，分别从前往后、从后往前存储，最后用两个关键字排起来

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int a[11];
bool cmp2(int a,int b){
	return a > b;
}
int main(){
	int tot = 1;
	int tt = 10;
	for(int i = 1;i <= 10; i++){
		int b;
		cin >> b;
		if(b % 2){
			a[tot++] = b;
		}else{
			a[tt--] = b;
		}
	}
	sort(a+1,a+tot,cmp2);
	sort(a+tot,a+11);
	for(int i = 1;i <= 10; i++) cout << a[i] << ' ';
	cout << endl; 
	return 0;
}

合影效果

这个门好麻烦啊

同上，最后只用输出身高

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
double s[1000];
bool cmp(double a,double b){
	return a > b;
}
int main(){
	cin >> n;
	int tot = 1,tt = n;
	for(int i = 1;i <= n; i++){
		string in;
		double b;
		cin >> in >> b;
		if(in == "male"){
			s[tot++] = b;
		}else{
			s[tt--] = b;
		}
	}
	sort(s+1,s+tot);
	sort(s+tot,s+1+n,cmp);
	for(int i = 1;i <= n; i++) printf("%.2f ",s[i]);
	cout << endl;
	return 0;
}

病人排队

看病的时候老人都要先看？？

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
struct PEO{
	string num;
	int age;
	int time;
}peo[1000];
bool cmp1(PEO a,PEO b){
	if(a.age != b.age) return a.age > b.age;
	return a.time < b.time;
}
bool cmp2(PEO a,PEO b){
	return a.time < b.time;
}
int main(){
	cin >> n;
	int tot = 1,tt = n;
	for(int i = 1;i <= n; i++){
		string in; 
		int b;
		cin >> in >> b;
		if(b >= 60){
			peo[tot].time = i;
			peo[tot].age = b;
			peo[tot++].num = in;
		}else{
			peo[tt].time = i;
			peo[tt].age = b;
			peo[tt--].num = in;
		}
	}
	
	sort(peo+1,peo+tot,cmp1);
	sort(peo+tot,peo+1+n,cmp2);
	
	for(int i = 1;i <= n; i++){
		cout << peo[i].num << endl;
	}
	return 0;
}

明明的随机数

YBT luogu

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
int a[1000];
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++) cin >> a[i];
	sort(a+1,a+1+n);
	int tot = 0;
	for(int i = 1;i <= n; i++){
		tot++;
		while(a[i+1] == a[i]) i++;
	}
	cout << tot << endl;
	for(int i = 1;i <= n; i++){
		cout << a[i] << ' ';
		while(a[i] == a[i+1]) i++;
	}
	return 0;
}

单词排序

我好像没有AC啊

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
string a[1000];
int main(){
	char c;
	int tot = 1;
	while(c != '
'){
		cin >> a[tot++];
		c = getchar();
	}
	sort(a+1,a+1+tot);
	for(int i = 1;i <= tot; i++){
		cout << a[i] << endl;
		while(a[i] == a[i+1]) i++;
	}
	return 0;
}

出现次数超过一半的数

出现次数超过一半的数

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
int a[5000];
int main(){
	cin >> n;
	for(int i = 1;i <= n; i++) cin >> a[i];
	sort(a+1,a+1+n);
	bool you = 0;
	for(int i = 1;i <= n; i++){
		int tot = 0;
		while(a[i] == a[i+1]){
			i++;
			tot++;
		}
		if(tot >= n/2){
			cout << a[i] << ' ';
			you = 1;
		}
	}
	if(!you) cout << "no" << endl;
	return 0;
}

统计字符数

看了吧我就是这么妥协的

#include<iostream>
#include<cstdio>
#include<algorithm>
using namespace std;
int n;
char a[10000];
int strlen(string a){
	int tot = 0;
	while(a[tot] != '') tot++;
	return tot;
}
int main(){
	cin >> a;
	for(int i = 9999;i >= 1; i--) a[i] = a[i-1];
	n = strlen(a);
	a[0] = '0';
	sort(a+1,a+1+n);
	char ans;
	int time = 0;
	for(int i = 1;i <= n; i++){
		int tim = 1;
		while(a[i] == a[i+1]){
			i++;
			tim++;
		}
		if(tim > time){
			time = tim;
			ans = a[i];
		}
	}
	cout << ans << ' ' << time << endl;
	return 0;
}