Create findTheCity.ts

Author: masx200

find-the-city-with-the-smallest-number-of-neighbors-at-a-threshold-distance/findTheCity.ts

@@ -0,0 +1,52 @@
+import { BinaryHeap } from "https://deno.land/std@0.165.0/collections/binary_heap.ts";
+export default function findTheCity(
+    n: number,
+    edges: number[][],
+    distanceThreshold: number
+): number {
+    const dc: [number, number][][] = new Array(n).fill(0).map(() => []);
+    const has: number[][] = Array(n)
+        .fill(0)
+        .map(() => Array(n).fill(distanceThreshold + 1));
+    const heap = new BinaryHeap<[number, number, number]>(
+        (a, b) => a[0] - b[0]
+    );
+
+    for (const [from, to, weight] of edges) {
+        if (weight <= distanceThreshold) {
+            dc[from].push([to, weight]);
+            dc[to].push([from, weight]);
+            heap.push([weight, from, to]);
+            has[from][to] = has[to][from] = weight;
+        }
+    }
+    for (let i = 0; i < n; i++) has[i][i] = 0;
+
+    while (!heap.isEmpty()) {
+        const [x, a, b] = heap.pop() as [number, number, number];
+
+        loop(b, x, a);
+        loop(a, x, b);
+    }
+    let minx = -1,
+        mnum = n + 1;
+
+    for (let x = n - 1; x >= 0; x--) {
+        const tep = has[x].filter((i) => i <= distanceThreshold).length;
+        if (tep < mnum) {
+            minx = x;
+            mnum = tep;
+        }
+    }
+    return minx;
+
+    function loop(b: number, x: number, a: number) {
+        for (const [i, j] of dc[b]) {
+            const r = j + x;
+            if (r < has[i][a]) {
+                heap.push([r, i, a]);
+                has[i][a] = has[a][i] = r;
+            }
+        }
+    }
+}