View Compilation Error

0_0_4184085_25972.cpp: In function `bool spfa()':
0_0_4184085_25972.cpp:65: error: `lt' undeclared (first use this function)
0_0_4184085_25972.cpp:65: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_4184085_25972.cpp:66: error: `rt' undeclared (first use this function)