闲的蛋疼，用 shell 写了个拓扑排序。。。

#!/usr/bin/env bash if graph="$(mktemp -d)" || { echo failed; exit 2; } then trap 'rm -rf "${graph}"' exit fi while read start end; do mkdir -p "${graph}/${end}/${start}" "${graph}/${start}" done while [[ $(ls -1 "${graph}" | wc -l) -gt 0 ]]; do for u in ${graph}/*; do [[ $(ls -1 "${u}" | wc -l) -eq 0 ]] && { echo "$(basename ${u})"; break; } done | { read pop || { echo cylic; exit 1; } echo "${pop}" rmdir "${graph}/${pop}" for v in ${graph}/*; do [[ -d "${v}/${pop}" ]] && rmdir "${v}/${pop}" done } done 

大家看看写得对吗？

附赠输入输出：

CSCI-E-50a CSCI-E-50b CSCI-E-50b CSCI-E-160 CSCI-E-160 CSCI-E-162 CSCI-E-50b CSCI-E-119 CSCI-E-119 CSCI-E-215 CSCI-E-119 CSCI-E-124 CSCI-E-50b MATH-E-104 MATH-E-10 CSCI-E-119 MATH-E-10 MATH-E-104 MATH-E-104 CSCI-E-124 

CSCI-E-50a CSCI-E-50b CSCI-E-160 CSCI-E-162 MATH-E-10 CSCI-E-119 CSCI-E-215 MATH-E-104 CSCI-E-124 

玩得开心～