gap.cpp: In function 'long long int findGap(int, int)':
gap.cpp:16:27: error: 'ref' is not a member of 'std'
16 | MinMax(l, r, std::ref(nl), std::ref(nr));
| ^~~
gap.cpp:16:41: error: 'ref' is not a member of 'std'
16 | MinMax(l, r, std::ref(nl), std::ref(nr));
| ^~~
gap.cpp:17:37: error: 'max' is not a member of 'std'
17 | if (fl != -1) mxdist = std::max(mxdist, nl-fl);
| ^~~
gap.cpp:18:37: error: 'max' is not a member of 'std'
18 | if (fr != -1) mxdist = std::max(mxdist, fr-nr);
| ^~~
gap.cpp:24:19: error: 'max' is not a member of 'std'
24 | mxdist = std::max(mxdist, fr-fl);
| ^~~