题意 link(more:129.,P1044) 简化题意:给定严格从 \(1\thicksim n\) 这 \(n(n\leqslant 6\times10^4)\) 个整数,规定每个数都要进出栈各一次,求所有可能的出栈序列的数量。 这题有多种做法(爆搜,递推,...
[leetcode] 130. surrounded regions 包围区域 given a 2d board containing 'x' and 'o'(the letter o), capture all regions surrounded by 'x'. a region is captured by flipping all...