{"trustable":false,"sections":[{"title":"","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 有N个学生合影,站成左对齐的k排,每行分别有N1,N2…NK个人,第一排站最后,第k排站之前。\u003cbr/\u003e\n学生身高依次是1…N。在合影时候要求每一排从左到右递减,每一列从后面到前也递减,一共有多少总方案\n \u003c/div\u003e"}},{"title":"Input","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 输入\u003cbr/\u003e\n每组测试数据包含两行。第一行给出行数k\u003cbr/\u003e\n第二行包含从后到前(n1,n2,…,nk)的行的长度,作为由单个空格分隔的十进制整数。\n\u003cbr/\u003e\n问题数据以0结束。\u003cbr/\u003e\nN\u003c\u003d30, k\u003c\u003d5;\n \u003c/div\u003e"}},{"title":"Output","value":{"format":"HTML","content":"\n \u003cdiv class\u003d\"ptx\" lang\u003d\"en-US\"\u003e\n 输出\u003cbr/\u003e输出每组数据的方案数\n \u003c/div\u003e"}},{"title":"Sample Input","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e1\n30\n5\n1 1 1 1 1\n3\n3 2 1\n4\n5 3 3 1\n5\n6 5 4 3 2\n2\n15 15\n0\n\u003c/pre\u003e"}},{"title":"Sample Output","value":{"format":"HTML","content":"\u003cpre class\u003d\"sio\"\u003e1\n1\n16\n4158\n141892608\n9694845\n\u003c/pre\u003e"}}]}