摘要： ~~四倍经验题~~ 简单线段树qwq~~（那你怎么还调了好几个小时）~~ 修改：$ans[cur]=(r l+1 ans[cur]);$ 点表示的区间有多长就是有多少盏灯 亮着的关掉 暗的开启 就是上述语句了。 cpp include include include include include 阅读全文