24-game.go

package problem0679

import (
	"sort"
)

// 无法算出 24 的数字组合
var bad = []int{1111, 1112, 1113, 1114, 1115, 1116, 1117, 1119, 1122, 1123, 1124, 1125, 1133, 1159, 1167, 1177, 1178, 1179, 1189, 1199, 1222, 1223, 1299, 1355, 1499, 1557, 1558, 1577, 1667, 1677, 1678, 1777, 1778, 1899, 1999, 2222, 2226, 2279, 2299, 2334, 2555, 2556, 2599, 2677, 2777, 2779, 2799, 2999, 3358, 3467, 3488, 3555, 3577, 4459, 4466, 4467, 4499, 4779, 4999, 5557, 5558, 5569, 5579, 5777, 5778, 5799, 5899, 5999, 6667, 6677, 6678, 6699, 6777, 6778, 6779, 6788, 6999, 7777, 7778, 7779, 7788, 7789, 7799, 7888, 7899, 7999, 8888, 8889, 8899, 8999, 9999}

func judgePoint24(nums []int) bool {
	sort.Ints(nums)
	sum := 0
	for i := 0; i < 4; i++ {
		sum = sum*10 + nums[i]
	}

	i := sort.SearchInts(bad, sum)

	return bad[i] != sum
}