欢乐纪中某B组赛【2019.1.21】

版权声明：原创，未经作者允许禁止转载 https://blog.csdn.net/Mr_wuyongcong/article/details/86577928

前言

成功翻车

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成绩

$Rank$是有算别人的

$Rank$	$Person$	$Score$	$A$	$B$	$C$
$14$	$2017hzb$	$80$	$30$	$0$	$50$
$14$	$2017wyc$	$80$	$0$	$30$	$50$
$14$	$2017xxy$	$80$	$30$	$0$	$50$
$44$	$2017lw$	$30$	$30$	$0$	$0$
$44$	$2017lrz$	$30$	$30$	$0$	$0$
$44$	$2017zyc$	$30$	$0$	$30$	$0$
$44$	$2017hjq$	$30$	$0$	$0$	$30$
$61$	$2017xjq$	$0$	$0$	$0$	$0$

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正题

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$T1:jzoj4208-$线段树什么的最讨厌了【 $dfs$】

博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86577063

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$T2:jzoj4209-$已经没有什么好害怕的了【差分】

博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86577360

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$T3:jozj4010-$我才不是萝莉控呢【哈夫曼树】

博客链接:
https://blog.csdn.net/Mr_wuyongcong/article/details/86577658

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$some\ of\ code$

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T2暴力

#include<cstdio>
#include<cstring>
#define ll long long
using namespace std;
const ll XJQ=1e9+7;
char s[1001];
ll n,ans[1001],sum,t;
int main()
{
	freopen("data.in","r",stdin);
	freopen("data.ans","w",stdout);
	scanf("%lld",&t);
	while(t--){
	scanf("%s",s+1);
	n=strlen(s+1);
	memset(ans,0,sizeof(ans));sum=0;
	for(ll i=1;i<n;i++)
	{
		for(ll j=i+1;j<=n;j++)
		{
			ll left=0;bool flag=1;
			for(ll k=i;k<=j;k++)
			{
			  	if(s[k]=='(') left++;
			  	else left--;
				if(left<0){
					flag=0;
					break;
				}
			}
			if(flag&&!left)
			  for(ll k=i;k<=j;k++)
			    ans[k]++;
		}
	}
	for(ll i=1;i<=n;i++)
	  sum+=ans[i]*i%XJQ;
	printf("%lld\n",sum);
	}
}

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T2随机数据

#include<cstdio>
#include<cstdlib>
#include<ctime>
using namespace std;
int t,n;
int main()
{
	freopen("data.in","w",stdout);
	srand(time(0));
	t=10;
	n=100;
	printf("10\n");
	for(int i=1;i<=t;i++)
	{
		//for(int j=1;j<=n/2;j++)
		 // printf("(");
		for(int j=1;j<=n;j++)
		 // printf(")");
		  if(rand()&1) printf(")");
		  else printf("(");
		printf("\n");
	}
}

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T2 30code

#include<cstdio>
#include<cstring>
#include<stack>
#define ll long long
using namespace std;
const ll N=1e6+10,XJQ=1e9+7;
stack<ll> left,mark,k;
ll t,n,ans,sum[N],ks,marks;
char s[N];
int main()
{
	freopen("data.in","r",stdin);
	freopen("data.out","w",stdout);
	scanf("%lld",&t);
	while(t--)
	{
		scanf("%s",s+1);
		n=strlen(s+1);
		ks=0;ans=0;marks=0;
		while(!left.empty()) left.pop();
		while(!mark.empty()) mark.pop();
		while(!k.empty()) k.pop();
		for(ll i=1;i<=n;i++)
		{
			sum[i]=sum[i-1]+i;
			if(s[i]==')'&&left.empty())
				marks=ks=0;
			else if(s[i]==')'){
				ll z=(sum[i]-sum[left.top()-1])%XJQ;
				left.pop();
				marks=mark.top();mark.pop();
				ks=k.top();k.pop();ks=(ks+1)%XJQ;
				(marks+=z*ks)%=XJQ;
				(ans+=marks)%=XJQ;
			}
			else{
				left.push(i);
				mark.push(marks);
				k.push(ks);
				marks=0;ks=0;
			}
		}
		printf("%lld\n",ans);
	}
}

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T3 50分code

#include<cstdio>
#include<algorithm>
#include<cstring>
using namespace std;
const int N=1e3+10;
int t,n,a[N],f[N][N*2];
int main()
{
	scanf("%d",&t);
	while(t--){
		scanf("%d",&n);
		a[n+1]=0;
		for(int i=n;i>=1;i--)
			scanf("%d",&a[i]);
		for(int i=1;i<=n;i++)
			a[i]+=a[i-1];
		memset(f,0x3f,sizeof(f));
		f[0][0]=0;
		for(int i=1;i<=n;i++)
		{
		  for(int j=n;j>=1;j--)
		    f[i][j]=min(min(f[i][j*2-1],f[i][j*2])+a[i],f[i-1][j-1]);
		}
		printf("%d\n",f[n][1]);
	}
}

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总结

开心，题目难一点就翻车了 $QVQ$。
$T1:$好像是 $dfs$，就写了一个，然后发现有一个地方直接写了 $return\ 0$。
愉快爆蛋。
$T2:$写了半天，和正解檫肩而过，写了一个先加后 $mod$就愉快30 $，不如暴力$QVQ$
$T3:$明显 $50$分 $dp$
$QVQVQ$