solved: 1283

Author: ryoppippi

code/1283.find-the-smallest-divisor-given-a-threshold.ts

@@ -0,0 +1,34 @@
+// @leet start
+
+/** TLE */
+// function smallestDivisor(nums: number[], threshold: number): number {
+//   for(let i = 1; i <= Math.max(...nums); i++) {
+//     const divSum = nums.reduce((acc, num) => acc + Math.ceil(num / i), 0);
+//     if(divSum <= threshold) {
+//       return i;
+//     }
+//   }
+//   throw new Error('No divisor found');
+// };
+
+/*
+ * as divisor grows, the sum of division of all numbers decreases
+ * so we can use binary search to find the smallest divisor
+ */
+function smallestDivisor(nums: number[], threshold: number): number {
+  let left = 1;
+  let right = Math.max(...nums);
+  while (left < right) {
+    /* calcutate mid */
+    const mid = Math.floor((left + right) / 2);
+    const divSum = nums.reduce((acc, num) => acc + Math.ceil(num / mid), 0);
+    if (divSum > threshold) {
+      left = mid + 1;
+    } else {
+      right = mid;
+    }
+  }
+  return left;
+}
+// @leet end
+