目录A-STringB-MinimumSumC-TreeRestoringA-STring用栈模拟一下即可，具体的，当栈顶出现形如ST时，将其弹出。#include<bits/stdc++.h>#definelllonglongusingnamespacestd;llRead(){ intsig=1; llnum=0; charc=getchar(); while(!isdigit(c))