✨ [997] Find the Town Judge

Author: enkr1

997/gpt_solution.js

@@ -0,0 +1,58 @@
+/**
+ * @param {number} n
+ * @param {number[][]} trust
+ * @return {number}
+ */
+function findJudge(n, trust) {
+  const inDegree = Array(n + 1).fill(0); // point in -> being trust
+  const outDegree = Array(n + 1).fill(0); // point out -> trust someonme
+
+  console.log(inDegree)
+  console.log(outDegree)
+
+  for (const [a, b] of trust) {
+    outDegree[a]++;
+    inDegree[b]++;
+  }
+
+  console.log(inDegree)
+  console.log(outDegree)
+
+  for (let i = 1; i <= n; i++) {
+    if (inDegree[i] === n - 1 && outDegree[i] === 0) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+function findJudge2(n, trust) {
+  const trustCounts = Array(n + 1).fill(0);
+
+  for (const [a, b] of trust) {
+    trustCounts[a]--;
+    trustCounts[b]++;
+  }
+
+  for (let i = 1; i <= n; i++) {
+    if (trustCounts[i] === n - 1) {
+      return i;
+    }
+  }
+
+  return -1;
+}
+
+
+// let x = findJudge(2, [[1, 2]]) // 2
+// let x = findJudge(4, [[1, 2], [1, 3], [2, 1], [2, 3], [1, 4], [4, 3], [4, 1]]) // 3
+// let x = findJudge(1, [])
+// let x = findJudge(3, [[1, 2], [2, 3]]) // -1
+let x = findJudge(3, [[1, 3], [2, 3], [3, 1]]) // -1
+// 1 2 3
+// 1 -> 3
+// 2 -> 3
+// 3 -> 1
+console.log("x")
+console.log(x)

997/my_solution.js

@@ -0,0 +1,57 @@
+/**
+ * @param {number} n
+ * @param {number[][]} trust
+ * @return {number}
+ */
+const findJudge = (n, trust) => {
+  if (1 === n) return 1;
+
+  // being trusted map
+  let map = new Map(), judge = -1;
+
+  for (let i = 0; i < trust.length; i++) {
+    // map.set(trust[i][0], (trustMap.get(trust[i][0]) || []).concat(trust[i][1]));
+    map.set(trust[i][1], (map.get(trust[i][1]) || []).concat(trust[i][0]));
+
+    if (n - 1 === map.get(trust[i][1]).length) {
+      judge = trust[i][1];
+      // return trust[i][1];
+    }
+  }
+
+  console.log("potential judge")
+  console.log(judge)
+  console.log(map)
+  console.log(map.get(judge))
+
+  // const isTrustingEachOther = (key, target) => {
+  //   if (map.get(key).includes(target)) return false;
+  // }
+
+  // console.log(map)
+  // for (let [key, trusters] of map) {
+  //   console.log("key:" + key + ", trusters:" + trusters)
+  //   for (let t of trusters) {
+  //     // isTrustingEachOther(t, key);
+  //     console.log(t)
+  //     if (!map.get(t)) continue;
+  //     if (map.get(t).includes(judge)) return -1;
+  //     // if (judge - 1 === map.get(t).length) return t;
+  //   }
+  // }
+
+
+//   console.log(map)
+//   console.log("judge:" + judge)
+
+  return judge;
+};
+
+
+let x = findJudge(2, [[1, 2]]) // 2
+// let x = findJudge(4, [[1, 2], [1, 3], [2, 1], [2, 3], [1, 4], [4, 3], [4, 1]]) // 3
+// let x = findJudge(1, [])
+// let x = findJudge(3, [[1, 2], [2, 3]]) // -1
+// let x = findJudge(3, [[1, 3], [2, 3], [3, 1]]) // -1
+console.log("x")
+console.log(x)

997/solution.js

@@ -0,0 +1,25 @@
+/**
+ * @param {number} n
+ * @param {number[][]} trust
+ * @return {number}
+ */
+const findJudge = (n, trust) => {
+  let map = new Map(), judge = -1;
+
+  for (let i = 0; i < trust.length; i++) {
+    map.set(trust[i][1], (map.get(trust[i][1]) || []).concat(trust[i][0]));
+
+    if (n - 1 === map.get(trust[i][1]).length) {
+      judge = trust[i][1];
+    }
+  }
+
+  for (let [key, trusters] of map) {
+    for (let t of trusters) {
+      if (map.get(t) && map.get(t).includes(key)) return -1;
+    }
+  }
+
+
+  return -1;
+};

README.md

@@ -55,6 +55,7 @@
 - [424. Longest Repeating Character Replacement](./424/)
 - [647. Palindromic Substrings](./647/)
 - [771. Jewels and Stones](./771/)
+- [997. Find the Town Judge](./997/)
 - [1791. Find Center of Star Graph](./1791/)
 - [1971. Find if Path Exists in Graph](./1971/)
 
@@ -90,5 +91,5 @@ Batch create in bash
 TODO: Add to TOC!
 -->
 ```ssh
-chapter=1971 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
+chapter=997 && mkdir ./$chapter && touch ./$chapter/my_solution.js && touch ./$chapter/solution.js && alias x="node ./$chapter/my_solution.js"
 ```