dew=[]
import random
for _ in range(20):
    dew.append(random.randrange(1,21))
print(dew)
count=[0]*20

for b in dew:
    count[b-1]+=1
print(count)
for p in range(len(count)):
    if count[p] > 1:
        print('{} occurs {}'.format(p+1,count[p]))
        
for p in range(len(count)):
    if count[p] == 1
 
:
        print('{} occurs {}'.format(p+1,count[p]))

dew=[]
import random
for _ in range(20):
    dew.append(random.randrange(1,21))
print(dew)
count=[0]*20
once=[]
multi=[]
for b in dew:
    if count[b-1]:
        continue
    if dew.count(b) > 1:
        multi.append(b)
        count[b-1]=dew.count(b)
        print(
 
'{} ouccur {}'.format(b,count[b-1]))
    if dew.count(b) == 1:
        once.append(b)
        count[b-1]=1
        print('{} ouccur {}'.format(b,count[b-1]))

dew=[]
import random
for _ in range(20):
    dew.append(random.randrange(1,21))
print(dew)
count=[0]*20

for b in dew:
    count[b-1]+=1
for b in
 
 range(len(count)):
    if count[b] > 1:
        print('{} ouccur {}'.format(b+1,count[b]))
    elif count[b] == 1:
        print('{} occur {}'.format(b+1,count[b]))

dew=[]
import random
for _ in range(20):
    dew.append(random.randrange(1,21))
print(dew)
count=[0]*20

once=[]
multi=[]
for b in dew:
    if dew.count(b) > 1:
        if b not in multi:
            multi.append(b)
    elif dew.count(b) == 1:
        once.append(b)
print('once: {} {}'.format(once,len(once)))
print('mulit: {} {}'.format(multi,len(multi)))
        

dew=[]
import random
for _ in range(20):
    dew.append(random.randrange(1,21))
print(dew)
count=[0]*20

state=[0]*len(dew)
once=[]
multi=[]

for b in range(len(dew)):
    
    if state[b]:
        continue
    flag=False
    for p in range(b+1,len(dew)):
        if state[p]:
            continue
        if dew[b] == dew[p]:
            flag = True
            state[p]=1
    if flag:
        multi.append(dew[b])
        state[b]=1
    else:
        once.append(dew[b])
            
print('once has {},length:{}'.format(once,len(once)))
print('multi has {},length:{}'.format(multi,len(multi)))