/in/foo.cc: In function 'void init()':
/in/foo.cc:23:19: warning: operation on 'j' may be undefined [-Wsequence-point]
        cin >> len[++j].rs >> len[j].re >> len[j].l;
                   ^~~
/in/foo.cc:24:12: warning: operation on 'j' may be undefined [-Wsequence-point]
        len[++j].re=len[j-1].rs;
            ^~~