https://leetcode.cn/problems/number-of-pairs-satisfying-inequality/

Author: masx200

README.md

@@ -10,6 +10,8 @@ leetcode 测试
 
 ##### 包含的内容如下
 
+https://leetcode.cn/problems/number-of-pairs-satisfying-inequality/
+
 https://leetcode.cn/problems/count-of-smaller-numbers-after-self/
 
 https://leetcode.cn/problems/remove-letter-to-equalize-frequency/

number-of-pairs-satisfying-inequality/index.ts

@@ -0,0 +1,28 @@
+import { BinaryIndexTree } from "../rank-from-stream-lcci/BinaryIndexTree.ts";
+export default function numberOfPairs(
+    nums1: number[],
+    nums2: number[],
+    diff: number
+): number {
+    for (const [i, x] of nums2.entries()) {
+        nums1[i] -= x;
+    }
+    const b = Array.from(nums1).sort((a, b) => a - b);
+    let ans = 0;
+    const t = new BinaryIndexTree(nums1.length);
+    for (const x of nums1) {
+        ans += t.query(lowerBound(b, x + diff + 1));
+        t.update(lowerBound(b, x) + 1, +1);
+    }
+    return ans;
+}
+export function lowerBound(a: number[], x: number) {
+    let left = 0,
+        right = a.length;
+    while (left < right) {
+        const mid = Math.floor(left + (right - left) / 2);
+        if (a[mid] < x) left = mid + 1;
+        else right = mid;
+    }
+    return left;
+}