В каждой клетке таблицы 4 × 5 стоит натуральное чи...
Created on: November 5, 2025
Answered using GPT-5 Thinking by Chat01
Created on: November 5, 2025
Answered using GPT-5 Thinking by Chat01
В каждой клетке таблицы 4 × 5 стоит натуральное число. При этом все числа различны, но суммы во всех строках одинаковы и во всех столбцах тоже одинаковы. Какова минимально возможная сумма чисел в таблице?
pythonimport itertools nums = list(range(1,20)) + [30] S = sum(nums) S 220
pythonnums = list(range(1,20)) + [30] sols = [] # find partitions into 5 groups of size 4 summing to 44 # This is large; use backtracking nums_set = set(nums) groups = [] nums_sorted = sorted(nums) count = 0 def search(available, start=0, groups=[]): if not available: yield groups[:] return # choose smallest remaining element to reduce symmetry a = min(available) # find 3 others b,c,d such that sum=44 rest = sorted([x for x in available if x!=a]) # Use combinations of 3 from rest for b,c,d in itertools.combinations(rest, 3): if a + b + c + [(1, 2, 11, 30), (3, 4, 18, 19), (5, 6, 16, 17), (7, 8, 14, 15), (9, 10, 12, 13)]
pythongroups = [ (1,2,11,30), (3,4,18,19), (5,6,16,17), (7,8,14,15), (9,10,12,13), ] import itertools # Represent assignment by, for each column, a permutation of indices 0..3 for rows # But we can think rows labeled 0..3. We'll generate row vectors by choosing for each column an index for row0, # etc and check if there exists alignment for all rows simultaneously. Equivalent to choose matrices of permutations. # We can brute force by backtracking across columns selecting a permutation for each column and tracking row sums. target_row_sum = 55 def backtrack(col, row_sums, perms): if col == len(groups): if all(rs == target_row_sum for rs in row_sums): yield perms[:] return g = groups[col] # Try all permutations of group g assigned to 4 rows for perm in itertools.permutations(g, 4): # prune by partial sums: any row sum exceed target? ok = True for r in range(4): if row_sums[r] + perm[r] > target_row_sum: ok = False break if not ok: continue # additional pruning: at last column, the needed value must equal remaining difference for each row # but that's automatic; skip row_sums2 = tuple(row_sums[r]+perm[r] for r in range(4)) perms.append(perm) yield from backtrack(col+1, row_sums2, perms) perms.pop() solutions = list(backtrack(0, (0,0,0,0), [])) len(solutions) 72
pythonsolutions[0] [(1, 2, 11, 30), (18, 19, 3, 4), (16, 6, 17, 5), (8, 15, 14, 7), (12, 13, 10, 9)]
pythonperm = solutions[0] row_sums = [sum(perm[c][r] for c in range(5)) for r in range(4)] col_sums = [sum(perm[c]) for c in range(5)] row_sums, col_sums ([55, 55, 55, 55], [44, 44, 44, 44, 44])
Минимальная сумма равна 220.
Почему:
Осталось показать достижимость . Возьмём набор (это сумма 220) и расположим так:
Проверка: суммы по строкам , по столбцам , все числа различны. Следовательно, минимально возможная общая сумма — 220.