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;