Binary Watch

class Solution {
public:
    vector<string> readBinaryWatch(int turnedOn) {
        vector<string> out;
        for (int h = 0; h < 12; ++h)
            for (int m = 0; m < 60; ++m)
                if (__builtin_popcount(h) + __builtin_popcount(m) == turnedOn)
                    out.push_back(to_string(h) + ":" + (m < 10 ? "0" : "") + to_string(m));
        return out;
    }
};

func readBinaryWatch(turnedOn int) []string {
    out := []string{}
    for h := 0; h < 12; h++ {
        for m := 0; m < 60; m++ {
            if bits.OnesCount(uint(h))+bits.OnesCount(uint(m)) == turnedOn {
                out = append(out, fmt.Sprintf("%d:%02d", h, m))
            }
        }
    }
    return out
}

from typing import List

class Solution:
    def readBinaryWatch(self, turnedOn: int) -> List[str]:
        out: List[str] = []
        for h in range(12):
            for m in range(60):
                if bin(h).count('1') + bin(m).count('1') == turnedOn:
                    out.append(f"{h}:{m:02d}")
        return out

var readBinaryWatch = function(turnedOn) {
    const popcount = (x) => {
        let c = 0;
        while (x) { c += x & 1; x >>>= 1; }
        return c;
    };
    const out = [];
    for (let h = 0; h < 12; h++) {
        for (let m = 0; m < 60; m++) {
            if (popcount(h) + popcount(m) === turnedOn) {
                out.push(`${h}:${m < 10 ? '0' : ''}${m}`);
            }
        }
    }
    return out;
};

class Solution {
    public List<String> readBinaryWatch(int turnedOn) {
        List<String> out = new ArrayList<>();
        for (int h = 0; h < 12; h++) {
            for (int m = 0; m < 60; m++) {
                if (Integer.bitCount(h) + Integer.bitCount(m) == turnedOn) {
                    out.add(String.format("%d:%02d", h, m));
                }
            }
        }
        return out;
    }
}

function readBinaryWatch(turnedOn: number): string[] {
    const popcount = (x: number): number => {
        let c = 0;
        while (x) { c += x & 1; x >>>= 1; }
        return c;
    };
    const out: string[] = [];
    for (let h = 0; h < 12; h++) {
        for (let m = 0; m < 60; m++) {
            if (popcount(h) + popcount(m) === turnedOn) {
                out.push(`${h}:${m < 10 ? '0' : ''}${m}`);
            }
        }
    }
    return out;
}