比赛 |
20150422 |
评测结果 |
AAAAAAAAAAAAAAA |
题目名称 |
奶牛跑步 |
最终得分 |
100 |
用户昵称 |
RP++ |
运行时间 |
0.867 s |
代码语言 |
C++ |
内存使用 |
2.22 MiB |
提交时间 |
2015-04-22 11:55:56 |
显示代码纯文本
#include <iostream>
#include <cstdio>
#include <algorithm>
#include <cstring>
using namespace std;
#define maxn 100010
#define lowbit(x) x&-x
#define LL long long
int n, tr[maxn];
LL end[maxn], num[maxn];
void Add(int x) {
for(int i = x; i <= n; i += lowbit(i))
tr[i]++;
}
int get_ans(int x) {
int ans = 0;
for(int i = x; i >= 1; i -= lowbit(i))
ans += tr[i];
return ans;
}
int find(LL x) {
int s = 1, t = n, mid;
while(s <= t) {
mid = (s + t) >> 1;
if(num[mid] >= x) t = mid - 1;
else s = mid + 1;
}
return s;
}
int main() {
freopen("cowjoga.in", "r", stdin);
freopen("cowjoga.out", "w", stdout);
LL t;
scanf("%d%lld", &n, &t);
LL s, v;
for(int i = 1; i <= n; i++) {
scanf("%lld%lld", &s, &v);
end[i] = s + v * t, num[i] = end[i];
}
sort(num + 1, num + n + 1);
int ans = 0;
for(int i = 1; i <= n; i++) {
ans += get_ans(n) - get_ans(find(end[i]) - 1);
Add(find(end[i]));
}
memset(tr, 0, sizeof(tr));
for(int i = n; i >= 1; i--) {
int tmp = get_ans(find(end[i]));
if(tmp) ans -= tmp - 1;
Add(find(end[i]));
}
printf("%d", n - ans);
}