【LeetCode】 401. Binary Watch

来源：互联网发布：oracle数据库查询语句编辑：程序博客网时间：2024/05/18 08:24

A binary watch has 4 LEDs on the top which represent the hours (0-11), and the 6 LEDs on the bottom represent the minutes (0-59).

Each LED represents a zero or one, with the least significant bit on the right.

For example, the above binary watch reads "3:25".

Given a non-negative integer n which represents the number of LEDs that are currently on, return all possible times the watch could represent.

Example:

Input: n = 1
Return: ["1:00", "2:00", "4:00", "8:00", "0:01", "0:02", "0:04", "0:08", "0:16", "0:32"]

Note:

The order of output does not matter.
The hour must not contain a leading zero, for example "01:00" is not valid, it should be "1:00".
The minute must be consist of two digits and may contain a leading zero, for example "10:2" is not valid, it should be "10:02".

public class Solution {    public List<String> readBinaryWatch(int num) {        List<String> res = new LinkedList<String>();        for (int i = 0; i < 12; i++) {            for (int j = 0; j < 60; j++) {                if (Integer.bitCount(i * 64 + j) == num) {                    res.add(String.format("%d:%02d", i, j));                }            }        }        return res;    }}

public class Solution {    private static String[][] hour = {{"0"}, {"1", "2", "4", "8"},             {"3", "5", "6", "9" ,"10"}, {"7", "11"}};    private static String[][] minute = {{"00"}, {"01", "02", "04", "08", "16", "32"},            {"03", "05", "06", "09", "10", "12", "17", "18", "20", "24", "33", "34", "36", "40", "48"},             {"07", "11", "13", "14", "19", "21", "22", "25", "26", "28", "35", "37", "38", "41", "42",                 "44", "49", "50", "52", "56"},             {"15", "23", "27", "29", "30", "39", "43", "45", "46", "51", "53", "54", "57", "58"},             {"31", "47", "55", "59"}};    public List<String> readBinaryWatch(int num) {        List<String> res = new LinkedList<String>();        int upper = Math.min(num, 3);        for (int i = 0; i <= upper; i++) {            if (num - i <= 5) {                for (String h : hour[i]) {                    int temp = num - i;                    for (String m : minute[temp]) {                        StringBuilder sb = new StringBuilder();                        sb.append(h).append(":").append(m);                        res.add(sb.toString());                    }                }            }        }        return res;    }}

0 0