https://leetcode.cn/problems/count-number-of-bad-pairs/

Author: masx200

README.md

@@ -10,6 +10,8 @@ leetcode 测试
 
 ##### 包含的内容如下
 
+https://leetcode.cn/problems/count-number-of-bad-pairs/
+
 https://leetcode.cn/problems/number-of-good-pairs
 
 https://leetcode.cn/problems/count-unique-characters-of-all-substrings-of-a-given-string

count-number-of-bad-pairs/index.ts

@@ -0,0 +1,13 @@
+function countBadPairs(nums: number[]): number {
+    const n = nums.length;
+    const cnt = new Map<number, number>();
+    for (const [i, num] of nums.entries()) {
+        cnt.set(num - i, (cnt.get(num - i) ?? 0) + 1);
+    }
+    const ans = Array.from(cnt.values()).reduce(
+        (a, v) => a + Math.floor((v * (v - 1)) / 2),
+        0,
+    );
+    return Math.floor((n * (n - 1)) / 2) - ans;
+}
+export default countBadPairs;

number-of-good-pairs/index.ts

@@ -1,11 +1,11 @@
-export default function numIdenticalPairs(nums: number[]): number {
-    const cnt = new Map<number, number>();
-    for (const num of nums) {
-        cnt.set(num, (cnt.get(num) ?? 0) + 1);
-    }
-    const ans = Array.from(cnt.values()).reduce(
-        (a, v) => a + Math.floor((v * (v - 1)) / 2),
-        0
-    );
-    return ans;
-}
+export default function numIdenticalPairs(nums: number[]): number {
+    const cnt = new Map<number, number>();
+    for (const num of nums) {
+        cnt.set(num, (cnt.get(num) ?? 0) + 1);
+    }
+    const ans = Array.from(cnt.values()).reduce(
+        (a, v) => a + Math.floor((v * (v - 1)) / 2),
+        0,
+    );
+    return ans;
+}