Compilare: main.cpp:13:18: warning: suggest parentheses around '+' inside '<<' [-Wparentheses] int cnt[(1 << 20 + 2)]; ~~~^~~ main.cpp: In function 'int main()': main.cpp:33:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < s1.size(); j++) ~~^~~~~~~~~~~ main.cpp:38:33: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = s1.size(); j < s2.size(); j++) { ~~^~~~~~~~~~~ main.cpp:59:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < s1.size(); j++) ~~^~~~~~~~~~~ main.cpp:64:25: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (int j = 0; j < s2.size()-s1.size(); j++) { ~~^~~~~~~~~~~~~~~~~~~~~