C :

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

typedef struct
{
	int no;
	int h,m;
	int tag;
}Node;

Node arry[105];


int main()
{
	int no,h,m;
	char op;
	int times,avetime;
	memset(arry,0,sizeof(arry));
	times = 0 , avetime = 0;
	while( scanf( "%d" , &no ) && no != -1)
	{
		scanf(" %c %d:%d" , &op , &h , &m );
		if( no == 0 )  //表示当前这组数据输入完毕，准备输出
		{
			if( times == 0 ) printf( "0 0\n" );  //如果输入次数为0的时候
			else
			{
                        //四舍五入
				if( avetime*1.0/times - avetime/times >= 0.5 )   avetime = avetime / times + 1;
				else    avetime = avetime/times;
				printf( "%d %d\n" , times , avetime );
			}
                  //清零，准备记录下一组数据
			memset(arry,0,sizeof(arry));
			times = 0 , avetime = 0;
		}
		else
		{
			if( op == 'S' && arry[no].tag == 0 )  //开始op == 'S'，并且以前没有开始过arry[no].tag == 0
			{
				arry[no].h = h , arry[no].m = m;
				arry[no].tag = 1;
			}
			else if( op == 'E' && arry[no].tag == 1 ) //结束op == 'E'，并且开始过arry[no].tag == 1
			{
				int time = (h-arry[no].h)*60 - arry[no].m + m;
				avetime += time;
				times++;
				arry[no].tag = 0;
			}
		}

	}
	return 1;
}

C++ :

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

int main() {
    while (true) {
        int k;
        scanf("%d", &k);
        if (-1 == k) break;
        char ss[10];
        int h, m, a[105], cnt = 0;
        double sum = 0;
        scanf("%s %d:%d", ss, &h, &m);
        fill(a, a + 105, -1);
        while (k > 0) {
            int x = h * 60 + m;
            if (ss[0] == 'S') {
                if (a[k] == -1)
                    a[k] = x;
            } else {
                if (a[k] != -1) {
                    sum += x - a[k];
                    ++cnt;
                    a[k] = -1;
                }
            }
            scanf("%d %s %d:%d", &k, ss, &h, &m);
        }
        if (0 == cnt)
            puts("0 0");
        else
            printf("%d %.0f\n", cnt, sum / cnt + 1e-8);
    }
    return 0;
}