蓝桥杯 第二十一天 贪心的一天
目录
1.1055. 股票买卖 II - AcWing题库
2.104. 货仓选址 - AcWing题库
3.122. 糖果传递 - AcWing题库
4.112. 雷达设备 - AcWing题库
5.1235. 付账问题 - AcWing题库
（1）有精度问题
（2）改良，仍有问题
6.1239. 乘积最大 - AcWing题库
7.1247. 后缀表达式 - AcWing题库
8.1248. 灵能传输 - AcWing题库
1.1055. 股票买卖 II - AcWing题库
n=int(input())
martix=list(map(int,input().split()))
ans=0
for i in range(n-1):
if martix[i+1]-martix[i]>0:
ans+=martix[i+1]-martix[i]
print(ans)2.104. 货仓选址 - AcWing题库
n=int(input())
martix=list(map(int,input().split()))
martix.sort()
ans=0
n//=2
for i in martix:
ans+=abs(i-martix[n])
print(ans)3.122. 糖果传递 - AcWing题库
离谱的一题
n=int(input())
martix=[]
for i in range(n):
martix.append(int(input()))
avg=sum(martix)//n
c=[0 for i in range(n+1)]
for i in range(n-1,0,-1):
c[i]=c[i+1]+avg-martix[i]
c[0]=0
martix=c[:n]
martix.sort()
res=0
half=martix[n//2]
for i in range(n):
res+=abs(c[i]-half)
print(res)4.112. 雷达设备 - AcWing题库
thread=[]
n,d=map(int,input().split())
flag=False
for _ in range(n):
x,y=map(int,input().split())
if y>d:
flag=True
break
change=(d*d-y*y)**0.5
thread.append((x-change,x+change))
if flag:
print(-1)
else:
thread.sort(key=lambda x:x[1])
point=thread[0][1]
ans=1
for i in range(1,n):
if point>=thread[i][0] and point<=thread[i][1]:
continue
else:
ans+=1
point=thread[i][1]
print(ans)5.1235. 付账问题 - AcWing题库
（1）有精度问题
import math
def out(martix):
avg=sum(martix)/n
sums=0
for i in martix:
sums+=pow(i-avg,2)
sums/=n
sums=math.sqrt(sums)
print("{:.4f}".format(sums))
return
n,s=map(int,input().split())
avg=s/n
m=list(map(int,input().split()))
nums=0
ans=[]
for i in m:
if i<=avg:
s-=i
ans.append(i)
else:
nums+=1
ans+=[s/nums for i in range(nums)]
out(ans)（2）改良，仍有问题
import math
n,s=map(int,input().split())
a=list(map(int,input().split()))
a.sort()
res=0
avg=s/n
for i in range(n):
cur=s/(n-i)
if a[i]6.1239. 乘积最大 - AcWing题库
n,k=map(int,input().split())
a=[]
for i in range(n):
a.append(int(input()))
a.sort()
res=1
l,r=0,n-1
sign=1
modss=1000000009
ans=[]
if k%2==1:
ans.append(a[r])
k-=1
res=a[r]
r-=1
if res<0:
sign=-1
res=res*sign%modss
while k:
x=a[l]*a[l+1]
y=a[r]*a[r-1]
if x*sign>y*sign:
res=x%modss*(res)%modss
ans.append(a[l])
ans.append(a[l+1])
l+=2
else:
ans.append(a[r])
ans.append(a[r-1])
res=(y%modss*res)%modss
r-=2
k-=2
print(res*sign)7.1247. 后缀表达式 - AcWing题库
n,m=map(int,input().split())
k=n+m+1
a=list(map(int,input().split()))
res=0
if m==0:
res=sum(a)
else:
a.sort()
res+=a[-1]-a[0]
for i in range(1,k-1):
res+=abs(a[i])
print(res)8.1248. 灵能传输 - AcWing题库
前缀和+贪心
t=int(input())
for _ in range(t):
n=int(input())
a=[0]+list(map(int,input().split()))
s=[0 for i in range(n+1)]
for i in range(1,n+1):
s[i]=s[i-1]+a[i]
s0=s[0]
sn=s[n]
if s0>sn:
s0,sn=sn,s0
s.sort()
s0=s.index(s0)
sn=s.index(sn)
st=[False for i in range(n+1)]
ans=[0 for i in range(n+1)]
l,r=0,n
for i in range(s0,-1,-2):
ans[l]=s[i]
l+=1
st[i]=True
for i in range(sn,n+1,+2):
ans[r]=s[i]
r-=1
st[i]=True
for i in range(n+1):
if not st[i]:
ans[l]=s[i]
l+=1
res=0
for i in range(1,n+1):
res=max(res,abs(ans[i]-ans[i-1]))
print(res)