library.cpp: In function 'void Solve(int)':
library.cpp:28:27: error: 'struct std::pair<int, int>' has no member named 'fr'
if (ar[i].fr == 0)
^~
library.cpp:29:27: error: 'struct std::pair<int, int>' has no member named 'fr'
ar[i].fr = j;
^~
library.cpp:31:27: error: 'struct std::pair<int, int>' has no member named 'sc'
ar[i].sc = j;
^~
library.cpp:33:27: error: 'struct std::pair<int, int>' has no member named 'fr'
if (ar[j].fr == 0)
^~
library.cpp:34:27: error: 'struct std::pair<int, int>' has no member named 'fr'
ar[j].fr = i;
^~
library.cpp:36:27: error: 'struct std::pair<int, int>' has no member named 'sc'
ar[j].sc = i;
^~
library.cpp:44:19: error: 'struct std::pair<int, int>' has no member named 'sc'
if (ar[i].sc == 0)
^~
library.cpp:54:37: error: 'struct std::pair<int, int>' has no member named 'fr'
if (!used[ ar[ ans[i - 1] ].fr ])
^~
library.cpp:56:39: error: 'struct std::pair<int, int>' has no member named 'fr'
ans[i] = ar[ ans[i - 1] ].fr;
^~
library.cpp:59:42: error: 'struct std::pair<int, int>' has no member named 'sc'
else if (!used[ ar[ ans[i - 1] ].sc ])
^~
library.cpp:61:39: error: 'struct std::pair<int, int>' has no member named 'sc'
ans[i] = ar[ ans[i - 1] ].sc;
^~
library.cpp:65:5: warning: this 'for' clause does not guard... [-Wmisleading-indentation]
for (int i = 0; i < n; i++)
^~~
library.cpp:68:2: note: ...this statement, but the latter is misleadingly indented as if it were guarded by the 'for'
Answer(ans);
^~~~~~