SRM 207 Div II Level One: TransportCounting

题目来源：http://community.topcoder.com/tc?module=ProblemDetail&rd=5853&pm=2928

这道题目看上去比较简单，但正解率只有70%，主要是要注意一下Example 4，起始位置为0的车也要算进去，所以Example 4答案是3而不是2。

代码如下：

#include <iostream>
#include <vector>

using namespace std;

class TransportCounting
{
public:
int countBuses(int speed, vector <int> positions, vector <int> velocities, int time);
};

int TransportCounting::countBuses(int speed, vector<int> positions, vector<int> velocities, int time)
{
int size = positions.size();

int yourDis, carDis, count;

yourDis = speed * time;
count = 0;
for (int i = 0; i < size; i++) {
if (0 == positions[i]) {
++count;
} else {
carDis = positions[i] + velocities[i] * time;
if (yourDis >= carDis) {
++count;
}
}

}
return count;
}