[BOJ] 4801 : Nine

#include <cstdio>
#include <algorithm>
using namespace std;

inline int calc(int n) {
    int r = 0;
    while (n) {
        r += n%10==9;
        n /= 10;
    }
    return r;
}

int main() {
    int h, m;
    while (scanf("%d:%d", &h, &m) && (h || m)) {
        int a = h*60+m;
        int rcnt = -1, rerr = 1e9, ri = -1, rj = -1;
        for (int i = 0; i <= 99; i++) for (int j = 0; j <= 99; j++) {
            int b = i*60+j;
            int cnt = calc(i)+calc(j), err = abs(a-b);
            if (err*10 >= a) continue;
            if (cnt > rcnt || (cnt == rcnt && err < rerr)) {
                ri = i, rj = j, rcnt = cnt, rerr = err;
            }
        }
        printf("%02d:%02d\n", ri, rj);
    }

    return 0;
}