一些比较抽象的题目

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1205. 买不到的数目

结论: 对于互质的两个数$p$，$q$，$px+py$不能表示的最大数为$pq-p-q$

证明

可以参考这篇

代码

n,m=MII()
print(n*m-n-m)

1211. 蚂蚁感冒

小思维题,想清楚,透过现象看本质

代码

import sys
from math import ceil,floor,fmod,gcd,sqrt,inf
from bisect import bisect_left
from collections import defaultdict,Counter,deque
from functools import lru_cache, reduce, cmp_to_key
from itertools import accumulate, combinations, permutations
from heapq import nsmallest, nlargest, heappushpop, heapify, heappop, heappush
from copy import deepcopy

limits = [100000, 10000, 5000, 2000]
for limit in limits:
    try:
        sys.setrecursionlimit(limit)
        break
    except:
        continue 

input = lambda: sys.stdin.readline().rstrip("\r\n")

def I():
    return input()
 
def II():
    return int(input())
 
def MII():
    return map(int, input().split())
 
def LI():
    return list(input().split())
 
def LII():
    return list(map(int, input().split()))

n=II()
a=LII()
l=r=0
p=abs(a[0])

# 头朝左 1   头朝右 0
f=int(a[0]<0)
for v in a:
    # 左边向右
    if abs(v)<p and v>=0:
        l+=1
    # 右边向左
    if abs(v)>p and v<0:
        r+=1
ans=1
if not ((f and l==0) or (not f and r==0)):
    ans+=l+r
print(ans)

1216. 饮料换购

大水题

代码

import sys
from math import ceil,floor,fmod,gcd,sqrt,inf
from bisect import bisect_left
from collections import defaultdict,Counter,deque
from functools import lru_cache, reduce, cmp_to_key
from itertools import accumulate, combinations, permutations
from heapq import nsmallest, nlargest, heappushpop, heapify, heappop, heappush
from copy import deepcopy

limits = [100000, 10000, 5000, 2000]
for limit in limits:
    try:
        sys.setrecursionlimit(limit)
        break
    except:
        continue 

input = lambda: sys.stdin.readline().rstrip("\r\n")

def I():
    return input()
 
def II():
    return int(input())
 
def MII():
    return map(int, input().split())
 
def LI():
    return list(input().split())
 
def LII():
    return list(map(int, input().split()))

n=II()

ans=n

while n>=3:
    p=n//3
    n%=3
    n+=p
    ans+=p
print(ans)