# Первый цикл поднимет a на 3, второй и третий на 0, 4-й на 2.
a = 1
for i in range(3):
a += 1
'''print(f'[for i in range(3) > RANGE][a = {a}]')'''
print(f'[for i in range(3) > TOTAL][a = {a}]')
a = 1
for i in range(3, 1):
a += 1
'''print(f'[for i in range(3, 1) > RANGE][a = {a}]')'''
print(f'[for i in range(3, 1) > TOTAL][a = {a}]')
a = 1
for i in range(1, 3, -1):
a += 1
'''print(f'[for i in range(1, 3, -1) > RANGE][a = {a}]')'''
print(f'[for i in range(1, 3, -1) > TOTAL][a = {a}]')
a = 1
for i in range(3, 1, -1):
a += 1
'''print(f'[for i in range(3, 1, -1) > RANGE][a = {a}]')'''
print(f'[for i in range(3, 1, -1) > TOTAL][a = {a}]')
8
Объяснение:
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 6 a[7] = 7 a[8] = 8 a[9] = 9 a[10] = 10
Берём значения i, n и a[i], подставляем формулу и считаем:
i = 1 n = 10 a[1] = 1
a[n+1-i]:=2*a[i]
a[10 + 1 - 1] = 2 * 1
a[10] = 2
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 6 a[7] = 7 a[8] = 8 a[9] = 9 a[10] = 2
i = 2 n = 10 a[2] = 2
a[n+1-i]:=2*a[i]
a[10 + 1 - 2] = 2 * 2
a[9] = 4
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 6 a[7] = 7 a[8] = 8 a[9] = 4 a[10] = 2
i = 3 n = 10 a[3] = 3
a[n+1-i]:=2*a[i]
a[10 + 1 - 3] = 2 * 3
a[8] = 6
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 6 a[7] = 7 a[8] = 6 a[9] = 4 a[10] = 2
i = 4 n = 10 a[4] = 4
a[n+1-i]:=2*a[i]
a[10 + 1 - 4] = 2 * 4
a[7] = 8
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 6 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 5 n = 10 a[5] = 5
a[n+1-i]:=2*a[i]
a[10 + 1 - 5] = 2 * 5
a[6] = 10
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 5 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 6 n = 10 a[6] = 10
a[n+1-i]:=2*a[i]
a[10 + 1 - 6] = 2 * 10
a[5] = 20
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 4 a[5] = 20 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 7 n = 10 a[7] = 8
a[n+1-i]:=2*a[i]
a[10 + 1 - 7] = 2 * 8
a[4] = 16
a[1] = 1 a[2] = 2 a[3] = 3 a[4] = 16 a[5] = 20 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 8 n = 10 a[8] = 6
a[n+1-i]:=2*a[i]
a[10 + 1 - 8] = 2 * 6
a[3] = 12
a[1] = 1 a[2] = 2 a[3] = 12 a[4] = 16 a[5] = 20 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 9 n = 10 a[9] = 4
a[n+1-i]:=2*a[i]
a[10 + 1 - 9] = 2 * 4
a[2] = 8
a[1] = 1 a[2] = 8 a[3] = 12 a[4] = 16 a[5] = 20 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
i = 10 n = 10 a[10] = 2
a[n+1-i]:=2*a[i]
a[10 + 1 - 10] = 2 * 2
a[1] = 4
a[1] = 4 a[2] = 8 a[3] = 12 a[4] = 16 a[5] = 20 a[6] = 10 a[7] = 8 a[8] = 6 a[9] = 4 a[10] = 2
Повторяющиеся значения:
a[1] = 4
a[9] = 4
a[2] = 8
a[7] = 8