PAT 乙级 1078

分析了半天，总算是分析对了。

#include<bits/stdc++.h> using namespace std; int main() { char c; cin >> c; getchar(); string s; getline(cin, s); if(c == 'C') { for(int i = 0; i < s.size(); i ++) { int begin1 = i; int end1 = i; while(end1 + 1 < s.size() && s[end1 + 1] == s[begin1]) end1 ++; if(end1 - begin1 > 0) cout << end1 - begin1 + 1 << s[begin1]; else if(end1 - begin1 == 0) cout << s[begin1]; i = end1; } } else if(c == 'D') { for(int i = 0; i < s.size(); i ++) { if(i > 0 && !isdigit(s[i]) && !isdigit(s[i - 1])) cout << s[i]; else if(i == 0 && !isdigit(s[i])) cout << s[i]; else if(isdigit(s[i])) { int begin1 = i; int end1 = i; while(end1 + 1 < s.size() && isdigit(s[end1 + 1])) end1 ++; int num = stoi(s.substr(begin1, end1 - begin1 + 1)); for(int j = 0; j < num; j ++) cout << s[end1 + 1]; i = end1; } } } return 0; }