Number of Ways to Wear Different Hats to Each Other

Given n people and 40 hat types where each person lists the hats they are willing to wear, count the assignments in which every person gets exactly one liked hat and no two people share a hat, modulo 10^9 + 7. Number of Ways to Wear Different Hats to Each Other Given n people and 40 hat types where each person lists the hats they are willing to wear, count the assignments in which every person gets exactly one liked hat and no two people share a hat, modulo 10^9 + 7. SWE dp state-compression-dp bitmask hard Frequency Single report Last asked 2026-04-01 Stage phone-screen Number of Ways to Wear Different Hats to Each Other There are n people and 40 possible hat types. hats[i] lists the hats person i is willing to wear. Return the number of valid assignments where every person gets exactly one hat they like and no two people wear the same hat, modulo 10^9 + 7. Examples Example 1: Input: hats = [[3,4],[4,5],[5]] Output: 1 Example 2: Input: hats = [[3,5,1],[3,5]] Output: 4 Constraints 1 <= hats.length <= 10 1 <= hats[i].length <= 40 1 <= hats[i][j] <= 40 Each hats[i] contains distinct values.