求助！10分，哪错了？

#include<bits/stdc++.h>
using namespace std;
int n, s1, s2, s = 1, t = 1, a[10005], b[10005], x;
double st, sd;
char c;
int main()
{
	cin >> n;
	for(int i = 1; i <= n; i++)
	{
		cin >> c;
		if(c == 'T')
		{
			cin >> x;
			s1++;
			a[s1] = x;
		}
		else
		{
			cin >> x;
			s2++;
			b[s2] = x;
		}
	}
	s2++;
	b[s2] = 1000;
	sort(a + 1, a + s1 + 1);
	sort(b + 1, b + s2 + 1);
	int la = 0;
	for(int i = 1; i <= s2 - 1; i++)
	{
		sd = b[i];
		st += (sd - la) / t;
		t++;
		while(sd < b[i + 1] && s <= s1 && st + (b[i + 1] - sd) * t > a[s])
		{
			sd += (a[s] - st) / t;
			t++;
			st = a[s];
			s++;
		}
		st += (b[i + 1] - sd) * t;
		la = sd;
	}
	cout << int(round(st));
	return 0;
}