Codeforces Round #629 (Div. 3)

目录

• 1328A
• 1328B
• 1328C

---

1328A

顺序结构

#include<iostream>
#include<cstdio>
using namespace std;

int main()
{
	int T; long long a,b,t;
	for(scanf("%d",&T);T;--T)
	{
		cin>>a>>b;
		if(a%b) t=a/b,cout<<b*t-a+b<<endl;
		else puts("0");
	}
	return 0;
}

---

1328B

和\(CSP2019-S~D1~T1\)很像，可是由于我的粗心大意，查错查了\(10minuts\)，还交了三次，痛心遗憾

#include<iostream>
#include<cstdio>
using namespace std;

void Solve1(unsigned long long k)
{
	if(k==1) printf("abb");
	if(k==2) printf("bab");
	if(k==3) printf("bba");
}

void Solve2(unsigned long long n,unsigned long long k)
{
	unsigned long long id=n-k+1;
	for(int i=1;i<=n;++i)
		if(i==id) putchar('b');
		else putchar('a');
}

void Dfs(unsigned long long n,unsigned long long k)
{
	if(n==3) {Solve1(k);return;}
	unsigned long long m;
	if(n&1) m=((n-1)>>1)*(n-2);
	else m=((n-2)>>1)*(n-1);
	if(k<=m) putchar('a'),Dfs(n-1,k);
        //一定是k<=m,不能写成k<m!!!    坑死我了!!!
	else putchar('b'),Solve2(n-1,k-m);
}

int main()
{
	int T; unsigned long long n,k;
	for(scanf("%d",&T);T;--T)
	{
		cin>>n>>k;
		Dfs(n,k),putchar('\n');
	}
	return 0;
}

---

1328C

简单地贪心与繁杂的字符串处理

#include<iostream>
#include<cstdio>
using namespace std;

void Read(int &x)
{
	x=0; char c=getchar();
	while(c<'0'||c>'9') c=getchar();
	x=c-'0';
}

int main()
{
	int T,flag;
	int n,num; string s;
	for(scanf("%d",&T);T;--T)
	{
		scanf("%d",&n); s="",flag=0;
		for(int i=1;i<=n;++i)
		{
			Read(num);
			if(flag)
			{
				putchar('0');
				if(num==0) s+='0';
				if(num==1) s+='1';
				if(num==2) s+='2';
			}
			else{
				if(num==0) {putchar('0'); s+='0';}
				if(num==1) {putchar('1'); s+='0'; flag=1;}
				if(num==2) {putchar('1'); s+='1';}
			}
		} putchar('\n');
		cout<<s<<endl;
	}
	return 0;
} 

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