{"problem":{"name":"计算线段长度","description":{"content":"已知线段的两个端点的坐标 `A(Xa,Ya)`，`B(Xb ,Yb)` ，求线段 AB 的长度。","description_type":"Markdown"},"platform":"Luogu","limit":{"time_limit":1000,"memory_limit":131072},"difficulty":{"LuoguStyle":"P1"},"is_remote":true,"is_sync":true,"sync_url":null,"sign":"LGB2030"},"statements":[{"statement_type":"Markdown","content":"已知线段的两个端点的坐标 `A(Xa,Ya)`，`B(Xb\n,Yb)` ，求线段 AB 的长度。\n\n## Input\n\n输入。\n\n共两行。\n\n第一行是两个实数 $Xa，Ya$，即 $A$ 的坐标。\n\n第二行是两个实数 $Xb，Yb$，即 $B$ 的坐标。\n\n输入中所有实数的绝对值均不超过 $10000$。\n\n## Output\n\n输出。\n\n一个实数，即线段 $AB$ 的长度，保留到小数点后 $3$ 位。\n\n[samples]","is_translate":false,"language":"English"}],"meta":{"iden":"LGB2030","tags":["顺序结构"],"sample_group":[["1 1\n2 2","1.414"]],"created_at":"2026-03-03 11:09:25"}}