Compilare: user.cpp: In function ‘int main()’: user.cpp:51:23: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (i = 0; i<C.size(); ++i) { ^ user.cpp:54:27: warning: comparison between signed and unsigned integer expressions [-Wsign-compare] for (j = 0; j<C[i].size(); ++j) ^ user.cpp:55:22: warning: suggest parentheses around ‘&&’ within ‘||’ [-Wparentheses] if (j == 0 || j>0 && C[i][j] != C[i][j - 1]) ^ user.cpp:37:18: warning: unused variable ‘a’ [-Wunused-variable] int n, i, x, y, a, b, sum = 0, m, j; ^ user.cpp:37:21: warning: unused variable ‘b’ [-Wunused-variable] int n, i, x, y, a, b, sum = 0, m, j; ^ user.cpp:37:24: warning: unused variable ‘sum’ [-Wunused-variable] int n, i, x, y, a, b, sum = 0, m, j; ^