View Compilation Error

0_0_39000208_20245.cpp: In function 'int main()':
0_0_39000208_20245.cpp:57:9: error: 'build' was not declared in this scope
   57 |         build(1, 0, ys.size() - 2);  //从1号点开始建线段树，对应的离散化后的坐标的取值范围是0~ys.size()-2 --> 2n-1个
      |         ^~~~~
0_0_39000208_20245.cpp:66:13: error: 'modify' was not declared in this scope
   66 |             modify(1, find(seg[i].y1), find(seg[i].y2) - 1, seg[i].k);  //把当前seg作用到线段树上
      |             ^~~~~~