renamed 2 digit file names

2018/07/part1.js

@@ -0,0 +1,22 @@
+const fs = require('fs');
+let rules = fs.readFileSync('input.txt', 'utf-8').split('\n');
+steps = [];
+for (let rule of rules) {
+	[_, step1, step2] = rule.match(/Step (\w) must be finished before step (\w) can begin./);
+	if (!steps[step1])
+		steps[step1] = []
+	if (!steps[step2])
+		steps[step2] = []
+	steps[step2].push(step1)
+}
+let ans = '';
+
+while (Object.entries(steps).length > 0) {
+	let step = Object.entries(steps).filter(v => v[1].length == 0).map(v => v[0]).sort()[0]
+	delete steps[step];
+	for (let step_ in steps) {
+		steps[step_] = steps[step_].filter(v => v != step)
+	}
+	ans += step
+}
+console.log(ans)