C 解法, 执行用时: 2ms, 内存消耗: 336KB, 提交时间: 2019-12-03

#include <stdlib.h>
#include <stdio.h>
#include <string.h>

void get_clock(char clock[][8], int h, int m)
{
    int byte = m / 8;
    int bit  = m % 8;
    char *p_clock = &clock[h][byte];
    int counter = 0;
    
    while( (*p_clock) == 0)
    {
        p_clock--;
        counter++;
    }
    
    if (counter != 0)
    {
        bit = 7;
        if (byte >= counter)
            byte -= counter;
        else
        {
            int rm_h = counter / 8;
            int rm_b = counter % 8;
            h -= rm_h;
            if (byte >= rm_b)
                byte -= rm_b;
            else
            {
                h--;
                byte = 8 + byte - rm_b;
            }
        }
    }
    
    while (1)
    {
        int tmp = (*p_clock) & (1 << bit);
        if (tmp)
            break;
        else
            bit--;
        
        if (bit < 0)
        {
            bit = 7;
again:
            p_clock--;
            byte--;
            if (byte < 0)
            {
                byte = 7;
                h--;
            }
            if ( (*p_clock) == 0)
                goto again;
        }
    }
    m = byte * 8 + bit;
    printf ("%d %d\n", h, m);
}

int main(int argc, char **argv)
{
    char clock_record[24][8];
    memset(clock_record, 0, sizeof(clock_record));
    int n;
    scanf("%d", &n);
    int i = 0;
    int h = 0;
    int m = 0;
    while (i < n)
    {
        scanf("%d %d", &h, &m);
        int l = m / 8;
        int r = m % 8;
        clock_record[h][l] |= (1 << r);
        i++;
    }
    int x, a, b;
    scanf("%d", &x);
    scanf("%d %d", &a, &b);
    
    if (x > b)
    {
        a--;
        b = 60 + b - x;
    }
    else 
        b = b - x;

    get_clock(clock_record, a, b);
    return 0;
}

C 解法, 执行用时: 2ms, 内存消耗: 344KB, 提交时间: 2019-08-03

int main()
{
    int n;
    scanf("%d",&n);
    int time[n];
            int hour,mine;
    for(int i=0;i<n;i++)
    {
 
        scanf("%d %d",&hour,&mine);
        time[i] = hour*60+mine;
    }
    int get_time;
    scanf("%d",&get_time);
    int lasthour,lastmine;
    scanf("%d %d",&lasthour,&lastmine);
    int lasttime = lasthour*60 + lastmine;
    int max=-1,maxhour=0,maxmine=0;
    for(int i=0;i<n;i++)
    {
        if(time[i]+get_time<=lasttime && time[i]>max)
        {
            max = time[i];
            maxhour = time[i]/60;
            maxmine = time[i]-maxhour*60;
        }
    }
    printf("%d %d",maxhour,maxmine);
}