Compilare: user.cpp: In function ‘void init()’: user.cpp:21:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < curr.size(); ) { ^ user.cpp:24:24: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] while(i < curr.size() && islower(curr[i])) ^ user.cpp: In function ‘int calc(int, int, int, int)’: user.cpp:33:22: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i >= s[id1].size() && j >= s[id2].size()) return 0; ^ user.cpp:33:44: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i >= s[id1].size() && j >= s[id2].size()) return 0; ^ user.cpp:38:26: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(j + 1 <= s[id2].size()) { ^ user.cpp:43:21: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] if(i < s[id1].size()) { ^ user.cpp: In function ‘void backk(int)’: user.cpp:61:32: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i + 1; j < s.size(); j++) { ^ user.cpp: In function ‘void solve()’: user.cpp:82:28: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 1; i < s.size(); ++i) { ^ user.cpp:92:29: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int i = 0; i < s.size(); ++i) ^ user.cpp:95:34: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for(int j = i + 1; j < s.size() && ok; ++j) { ^