問題描述

n = int(input())
num = [[0 for col in range(n)] for row in range(n)]
for x in range(n):
    tlist = list(map(int, input().split()))
    for y in range(n):
        num[x][y] = tlist[y]
outp = [[] for col in range(2 * (n - 1) + 1)]
for x in range(n):
    for y in range(n):
        outp[x + y] += [num[x][y]]
cot = -1
count = []
for i in range(2 * (n - 1) + 1):
    if cot == -1:
        outp[i].reverse()
        count += outp[i]
    else:
        count += outp[i]
    cot *= -1
for p in count: print(p, end=" ")
 

把xy座標和相同的歸為一組 共有2*（n-1）組 

正反索引